Apvil 7, 1871.] 1 02 [Cope. 
Anguilla include remains of twelve vertebrates,* of which seven are 
mammalia of extinct species, and several of them are of large size. These 
are associated with the recent species of molluscs Turbo pica and a 
Ludora near pupaformis.; As these large animals no doubt required a 
more extended territory for their support than that represented by the small 
island Anguilla, there is every probability that the separation of these 
islands took place at a late period of time and probably subsequent to the 
spread of the postpliocene fauna over North America. 
EXPLANATION OF THE. CUTS. 
Figs. 1-12. Sections of teeth of Megalonyx of the natural size. 
Fig. 1-2. Sections of canine-molars of Mf. loxodon, Cope ; 2a, profile of 
2 from within. 
Figs. 3-6. Sections of canine-molars of Megalonyx wheatleyt, Cope; da 
side view of 4 from the inner side. 
Figs. 7-8. Sections of canine-molars of ? Megalonyx dissimilis, Leidy, 
or of M. wheatleyi, Cope. 
Fig. 9. Sections of crowns of the superior molars of the right side of 
Megalonyx wheatleyi ; from separated teeth, the anterior probably of this 
species. 
Fig. 10. Sections of crowns of the inferior molars of the right side of 
M. wheatley?, from specimens in place in jaw. 
Fig. 11. Crown of tooth of Megalonyx sphenodon, Cope; ila, same 
from the inside. 
Fig. 12. View of canine-molar of Megalonyx tortulus seen from the 
crown ; 12a, inner view of same tooth. 
Fig. 18. Grinding surfaces of left inferior molars of Arvicola speothen, 
Cope, enlarged. 
Fig 14, Grinding surfaces of second and third superior molars of 
Arvicola tetradelta, Cope. 
Fig. 15. Same of Arovicola didelta, Cope, enlarged; a, b, ¢, of the first 
inferior molar; d, of the superior molars. 
Fig. 16. First inferior molar grinding surface of Arvicola involuta, Cope, 
enlarged. 
Fig. 17. Same of Arvicola sigmodus, Cope, enlarged; a, b, ¢, of first 
inferior molar; d, of superior molars. 
Fig. 18. Same of Arvicola hiatidens, Cope, enlarged ; a superior molar 
1 or 2, incomplete; b, 8d superior molar; c, 1st inferior. The entering 
folds should not be in contact in figs. @ and d, in cuts. 
Fig. 19. Grinding surface of last superior molar of Hrithizon cloacinum, 
Cope, natural size. 
Fig. 20, Superior molar teeth (incomplete) of Praotherium palatinum, 
Cope, natural size. : 
* Loc. cit. 1869. 183; 1870, 608. A fourth species of gigantic Chinchillid has been found by Dr. 
Rijgersma, which may be called Loxomylus quadrans, Cope. It is represented by portions of jaws 
and teeth of three als. It is one of the largest species, equalling the L, latiden and has 
several marked ch s. Thus the roots of the molars are very short, and the triturating 
surface oblique to the shaft. The roots of the second and fourth are longer than those of the first 
and third. ‘The last molar has four dental columns instead of three as in the other Loxomyli, and is 
triangular or quadrant-shaped in section; the third is quadrangular in section, and has three columns. 
‘The second nallest, being only .6 the length of the subtriangular, first. Length of dental 
series m. 063 0 5inches. Palate narrow and deeply concave. ‘There is but little or no lateral 
constriction in the outlines of the teeth; the shanks are entirely straight. In its additional 
dentinal column, this species approaches the genus Amblyrhiza, 
The large Chinchillas of Anguilla are as follows, Loxomylus longidens, L, latidens, L. quadrans and 
Amblyrhiza inundata, 
} See Bland, Proceed. Amer, Phil. Soc., 1871, 58. 
