INTRODUCTION. !)
now being partly genetic, partly adaptive. ‘To test (if test it can be called) this hypothesis, I compared our Tortoises with those of the neighbouring continents, but did not succeed in finding any evidence in their osseous frame which might be used as argument in favour of such direct genetic relationship. In none have I found the singular modification of the articulations of the nuchal vertebre of the Aldabra Tortoise.
The naturalists who maintain a common origin for allied species, however distant in their habitats, will have to assume a former continuity of land (extending over 150° of longitude, but probably varying in extent, and interrupted at various periods) between the Mascarenes and Africa, between Africa and South America, and, finally, between South America and the Galapagos. A continuity of land in this direction is more probable than one in the opposite hemisphere, which would extend over 210°. Indeed the terrestrial and freshwater faune of Tropical America and Africa offer so many points of intimate relationship as very strongly to support such a theory. The Tortoises, then, would be assumed to have been spread across the whole of this large area, without being able long to survive the arrival of man or large carnivorous mammals. The former, especially before he had provided himself with missile weapons, would eagerly seek for them, as they were the easiest of his captures, yielding a most plentiful supply of food; consequently they were exterminated on the continents, only some remnants being saved by having retired into places which, by submergence, became separated from the mainland before their enemies followed them. The discovery of bones of Tortoises in Malta, which seem to be almost identical with the corresponding parts in Galapagos Tortoises, as stated in a paper read before the Geological Society only a short time ago by Dr. Leith Adams, clearly proves the much greater extension of this Chelonian type at a former geological epoch.
10 SYNOPSIS OF THE EXTINCT AND LIVING GIGANTIC LAND-TORTOISES. BrEroreE proceeding to the detailed description of the various forms, I propose to indicate in a short synopsis the systematic results obtained in the following pages. I. Nuchal plate present. Frontal portion of the skull convex. Third cervical vertebrabiconver.Pelviswithnarrowsymphysialbridge.Gularplate double. Carapace thick. . . . «. « % =°. «w «© « «© 6 4). eADDABRAMLORTONsHC: 1. Shell broad, declivous in front; scutes striated. Skull broad, with the posterior margin of the paroccipital not excised. . . . . . 1. Testudo elephantina (living).
2.Shellnarrow,withhorizontalanteriorprofile;scutesalmostentirely smooth.Sternumtruncatedinfrontandbehind.Skullbroad,with the posterior margin of the paroccipital deeply excised. . . . . . 2. T. daudinii (living 7).
3.Shellregularlyelliptical,declivousinfront;scuteswithshallowstriation. Sternum notched behind. Skull narrow, with the posterior marginoftheparoccipitalnotexcised;astyloidprocessoneachside of the occipital condyle {2° 5) 4. §. 050) ee eee er een On eros (living).
4, Shell regularly elliptical, declivous in front ; scutes quite smooth. Sternum truncated behind. Skull Dip eo OEs i Gee c ume oloresse (living).
iT apd) f II. Nuchal plate absent. Frontal portion of the skull flat. Fourth “cervical vertebra biconvexr.
Pelvis with broad symphysial bridge.
A. Gular plate single; sternum short . . . .. . 2 3 9.9. «, . =) MiAschrennilorrorsms: gv.Carapacethin,thickenedtowardsthemargins;centreofthelastvertebral plate raised into a hump, which is separated from the penultimate vertebral by a transverse depression. . . . . . . . Tortoises of Mauritius (extinct). Shelldepressed,withtheupperprofileundulated,slightlydeclivousin front.Lowerjawwithatrebledentalridge.Horizontaldiameterof pelvis not longer than vertical, ©.) 27 292g) OR iserrnata (an=T.grayi?).
2.
SYSTEMATIC SYNOPSIS. 11 Shellhigh,withtheupperprofileconvex,declivousinfront.Lower jaw with double dental ridge. Vertical diameter of pelvis longer than horizontal . .. . eee ee One ezepia, 3.Shellwiththeupperprofilestraight,notdeclivousinfront.(Known iromthe'shell-only.) . 3. 4 6 3 2s as oo © «@. L. nmea: 4.Knownfromscapula,pelvis,andfemuronly,thelatterbonesbeing more slender thanin5and6 ..... . =... =. . . . 8. T. leptocnemis. b.Theentirecarapaceextremelythin;allthebonesveryslender.RodriguezTortoise(extinct). 5.Mandiblewithtwodentalridges;thesixthcervicalvertebrawithapair ofdeephollowsorperforations.Shellnotdeclivousinfrontinthe male, without vertebral humps. . . .. . =... + . . « 9 FT. vosmeri. B. Gular plate double; sternum of moderate extent . . . . . . . . Gatapagos TorrTolszs. 1.Shellbroad,depressed,withtheupperanteriorprofilesubhorizontalin themale;platesstriated;sternumtruncatedbehind.Outerpterygoid-edgesharp;adeeprecessinfrontoftheoccipitalcondyle..10.7.elephantopus (James Isl.? Living).
.Shellbroad,high,withdeclivousanteriorprofileinthemale;plates striated;sternumexcisedbehind.Outerpterygoid-edgesharp;a deep recess in front of the occipital condyle . . . . . . . . AL. T. nigrita (Isl. —? Living).
Shell rather narrow, depressed, with the upper anterior profile subhorizontalinthemale;platesstriated;sternumconstrictedinfrontand excisedbehind.Outerpterygoid-edgeflattened;norecessinfront of the occipital condyle. Tympanic opening circular . . . . . 12. T, vicina (SouthAlbemarle?Living).
.Shelldepressed,withtheanteriorupperprofilestraightinthemaleand declivousinthefemale;platesnotstriatedintheadult.Sternum withshortlobes,andtruncatedbehindintheadult.Outerpterygoid-edgesflattened,scarcelyconvergingbehind.Norecessinfront Olthe occipital condyle = 2 2 2 1 2 a1. » s » 2 » « « 1b. Do microphyes (NorthAlbemarle.Living).
Shellelongate,compressed,andnotdeclivousinfront,inthemale; plates smooth in the adult; sternum truncated behind. Outer pterygoid-edgesflattened,scarcelyconvergent;palateshallow.No recess in front of the occipital condyle . . . . . . . . . . 14. T. ephippium (IndefatigableIsl.Extinct).
.Shellelongate,compressed,andnotdeclivousinfront,inthemale; platesnotstriatedintheadult;sternumtruncatedbehind.Jaws white.
Outer pterygoid-edges flattened, rapidly converging behind.
Palatedeeplyconcave.Adeepimpressioninfrontoftheoccipital CONGVICE an geeeh oe He dots ay ee ee et es ow = os) LO: To abingdony (Abingdon.Living).
12 .Adult¢,stuffed. LIST OF SPECIMENS. List oF SPECIMENS OF GIGANTIC LanD-TortoIsEs, LIVING AND EXTINCT, IN THE CoLLECTIONOFTHEBritisHMusEum. 1.
TEstTUuDO ELEPHANTINA. .Adult¢,stuffed. Carapace 39 in.
.Skullofa. Carapace 49 in.
.Skeletonofc. .Adult?,stuffed. Carapace 27% in.
.Skullofe. g.
Young. p- VE .Veryyoung,inspirits. Carapace 14 in.
eAdultg. Carapace 40 in.
. Adult ¢. Carapace40in.,withoutscutes. .Skeletonofhalf-grown¢. Carapace 31 in., sternum missing. Half-grown 3.
Carapace 293 in.
.Veryyoung,stuffed. . Skull of adult ¢. Skull of half-grown spec.
Twohumeriofadult. *.
Scapula of adult. .Femurofadult. .
Young, malformed. Carapace 123 in.
Aldabra. Aldabra. 74.2.6.3. 74,2.6.4. Purchased. life Be.
Wits, 11, 77.0,15.2. 74,2.6.1. 74,2.6.2. FromtheHaslarCollection. 55.10.16.151. PurchasedofMr.Bartlett. Thi2hNB,2 Old Collection. ilo Gi Prob ile 74,2.6.8. FromtheR.Coll.ofSurgeons. (Oo ds Laced, Pres.byCol.Playfair. iatisWeUr Pres.byGeneralHardwicke. 16.
5.
16.
a.
Purchased. 76.11. 21. 2-3. Purchased.76.11.21.1. Purchased. 76. 11. 21. 4. Purch.oftheZool.Soc.
LIST OF SPECIMENS. 13 2.
TESTUDO DAUDINII.
.Adult¢@,stuffed. Carapace 343 in. 74. 2. 6. 5. . Skull of a. 74, 2. 6. 6. . Bones of forearms and lower legs of a. 74, 2. 6. 6. 3.
TestUDO PONDEROSA.
. Adult ?, skeleton. Purchased. 64. 12. 20. 27. Carapace 27% in.
. Pelvis of adult. Purchased. 76. 1. 4. 1. 4.
TEsTUDO HOLOLISSA.
. Adult 2, living. Aldabra. Purchased. Carapace 32 in.
5.
TESTUDO TRISERRATA.
. Skull of adult. Mare aux Songes. Pres. by E. Newton, Esq. . Mandible. - Pres. by Col. A. E. H. Anson. 39929. . Fragment of cranium. es Ditto. 39928. . Fragment of carapace. FP Ditto. 39964. . Sternum. 3 Pres. by E. Newton, Esq. . Two left scapularies. o Pres. by Col. A. E. H. Anson. 39939&39941.
. One right scapulary. : Ditto. 39940. h. Four humeri. As Ditto. 39942, 39945-47. 1. Four pelves. Fr Ditto. 39932-35. 6.
TestuDoO INEPTA.
. Skull of adult. Mare aux Songes. Pres. by Col. A. E. H. Anson. 39927. . Skull of adult. 3 Pres. by E. Newton, Esq. . Carapace without sternum. Pres. by L. Bouton, Esq. . Fragment of carapace with part of first rib. ,, Pres. by Col. A. E. H. Anson. 39963. . Right scapulary. i Ditto. 39937.
14 LIST OF SPECIMENS.
f. Left scapulary. Mare aux Songes. Pres. by Col. A. E. H. Anson. 39938. g. Two left humeri. A Ditto. 39943-44. h. Pelvis. As Ditto. 39931. it. Pelvis. 53 Purchased of Mr. Bewsher. 75.10:20)1.
7.
TEstTUDO LEPTOCNEMIS.
a. Two right scapularies. District of Flacq. Pres. by L. Bouton, Esq. 76.11.4.12-18.
6. Four fragments of pelvis. ee Ditto. 76.11. 4. 14-17. c. Two left femurs. or; Ditto. 76.11. 4. 10-11. * SPECIES INCERTA.
a. Fifth cervical vertebra. Mare aux Songes. Pres. by Col. A. E. H. Anson. 39980. b. Left scapula (“ 7. boutonii”’) B Ditto. 39936. c. Left ulna. * Ditto. 39948. d, Right ulna. i, Ditto. 39949. e. Left radius. es Ditto. 389951. f. Three right radii. a Ditto. 39950, 39952-3. g. Three left femurs. a Ditto. 39954-6. h. Three right femurs. < Ditto. 389957-9. i. Left tibia. 7 Ditto. 39960. k. Right tibia. Fe Ditto. 39961. 1. Right fibula. ss Ditto. 39962. 8.
TESTUDO VOSMERI.
AllthespecimensarefromRodriguez. a. Skulls and fragments of skulls of various sizes. “ Transit-of-Venus ” Collection. (ool 20:
b. More or less incomplete sets of cervical vertebre of Ditto. 76.11. 1. 21-49. various sizes.
c. Fifth cervical vertebra (fig.). Ditto; 76a desali72 d. A set of three cervical vertebre (fig.). Ditto 3/6 we as:
mM.
= LIST OF SPECIMENS. .Fifthandseventhcervicalvertebre. .Sixthandseventhcervicalvertebre. .Elevendorsalvertebra. .
Seventeen caudal vertebre. .Fivecarapacesofhalf-grownandyoungindividuals. .Sixpairsofscapuleeandseveraloddonesofvarioussizes. .Onescapula(fig.). Another scapula.
,Threepairsofhumeriandseveraloddonesofvarious S1Zes.
.Ahumerus(fig.). .
Two humeri.
.Severalrightandleftulne. .Twootherulne(fig.). .Severalrightandleftradii. .Pelvesofvarioussizes. .Twootherpelves(fig.). .Twootherpelves. .Severalrightandleftfemurs. »,Twootherfemurs(fig.). .Severalrightandlefttibi. .Righttibia. .Severalrightandleftfibule. 8.Anotherfibula(fig.). .
Two metatarsal bones.
.
Nine phalanges. 15 Pres.byL.Bouton,Esq. 76.11.4.6-7. Ditto. 76.11. 4. 1-2. «‘ Transit-of- Venus ” Collection. 76) Weds ode Ditto. (76. I. F, 50: Ditto. 76.11. 1. 52-56. Ditto. 76.11. 1. 57-64. Ditto, 70, DI. 115: Pres.byL.Bouton,Esq. 7051L4.9, “«‘ Transit-of- Venus ” Collection. 76.11.1.65-68. Ditto. 76. 11.1. 114. Pres.byL.Bouton,Esq. 76.11.4.8: ««Transit-of- Venus” Collection. Toy, AU, ALS GS SrAL Ditto. 76. 11. 1. 120. Ditto. 76.11. 1. 72-76. Ditto; ~76. 11. be 7-98; Ditto. 76. 11. 1. 113. Pres.byL.Bouton,Esq. 76. 11. 4. 4-5. “¢ Transit-of-Venus” Collection. 76.11.1.99-100. Ditto 76. Li IG: Ditto. 76.11. 1. 101-104. Pres.byL.Bouton,Esq. 76.11.4.3. ‘“‘Transit-of-Venus” Collection, 76.11.1.105-108. Ditto. 76.11. 1.119. Ditto, 76. IT. 1: 109: Ditto. 76.11, 1. 110:
16 a, a.
b.
f 1.Veryyoung,stuffed. Us Skeleton of young. Adult¢. LIST OF SPECIMENS. 9.
TrestUDO ELEPHANTOPUS. Galapagos. 10.
TEstuDO NIGRITA. Carapace 41 in.
(without sternum). Skeleton of young. Carapace16in.long. .Skeletonofyoung. Carapace152in.long. Young, stuffed. Carapace10in.long. Young, stuffed. Galapagos. Galapagos. (SeeProc,Zool.Soc.1870,pl.xli.) Carapaces6,54,and43in.long. Veryyoung,shell. Carapace32in.long. Skullofadult. (T.
planiceps, Gray.) .Skeletonofadult. .Skullofadult. .
Young, stuffed. Carapace 123 in.
.Skullofc. . Adult g (still living). Carapace 333 in.
. Adult g. Carapace 333 in.
.Skullof0. 11.
Trestupo vicina. IguanaCove,S.Albemarle. Pres.byCapt.E.M.Leeds. 76.10.23.1. Purchased. PresentedbyDr.Gunther. 16NO23m. 47.3.5. 27. FromtheHaslarCollection. Purchased. 70. 12. 18. 1. Pres.byDr.Gray. FromtheHaslarCollection. 48.4.6.3. Obtained by exchange. TA aD ie CommanderCookson’sCollection. 74,6,21.43. 74.6.1.4. (ASOwo. 12.
TrEsTUDO MICROPHYES. Tagus Cove, North Albemarle. Commander Cookson’s Collection. Ditto. 76. 6. 21. 41. Ditto. 76. 6. 21. 41.