OCR Text |
Show 402 MR. G. E. DOBSON ON THE [Mar. 1, Genus E R I N A C E U S , L. In the form of the head and body all the known species agree together remarkably closely ; and, as might be expected, the anatomy of these parts is much the same throughout the species ; but the limbs, being nearly free from the great panniculus carnosus (which as it were moulds the shape of the parts included within it), vary very considerably in form and relative length of parts ; and this variability is accompanied by differences in their internal structure not less remarkable than have been observed between the species of some other genera of Mammalia less closely allied by general external similarity of form. The anatomy of the following twelve species has been examined by the writer :- f 1. E. europceus, L. 2. E. concolor, Martin. Palaearctic Region .<( 3. E. algirus, Duvernoy. 4. E. deserti, Loche. ^ 5. E, macracanthus, Blanford. xvi • • T> • f 6. E. diadematus, Wiirtt. Ethiopian Region.. { „ w , . ,'. 0 , r ° [ 7. JL. heterodactylus, bund. C 8. E. micropus, Blyth. 9. E. pictus, Stoliczka. Oriental Region . . -^ 10. E. grayii, Bennett. | 11. E. blanfordi, Anderson. These species sufficiently r1e^p1r2e.s eEn.t ntihgee gre,n uBsl a;n footrhde.r known forms will be found to be closely related to one or other of them. With the exception of the head and tail, the skeleton of anv species of Erinaceus (for all resemble one another closely) resembles that of Gymnura with all the processes of the vertebrae shortened and the prominences of the other hones rounded off. The form of the skull differs considerably: it is altogether shorter and broader than in that genus ; the brain-case is comparatively more capacious, and the occipital crest much less developed. In other respects, however, there is much similarity; and the dentition is evidently but a modified form of that of Gymnura. If the dental formula of the latter he represented as follows :- • 3-3 1-1 4-4 3-3 ... ,, *• 3"-Z3> c- I=I» Vm- 4=4. m- 3=3 = 4 4 teeth, then that of Erinaceus is o-o 1-1 3-3 3-3 c\ n A. i\ *• %?%> c- I=I> Pm' 2-2' m- 3-Z3 = ,:>" teeth. By modifying the usual manner of writing the dental formula, the homologies l of the teeth of the latter with those of the former genus may be thus graphically expressed:- 1 As determined by the writer on grounds which are fully stated in the work referred to in note to p. 389. |