| OCR Text |
Show 1875.] RED BLOOD-CORPUSCLES. 483 ference is swollen, so as to produce triangular, oval, or formless pits towards the centre. In the Tables of Measurements only the regular blood-disks are noted. Of the Apyrensemata the Camels (figs. 37- 41) alone have oval red blood-corpuscles; but these, as before mentioned, conform in all other respects to the apyrensematous type ; and a few subrotund or circular disks may occur among the prevailing oval ones. In some Cervidse the corpuscles (fig. 42) assume fusiform, lanceolate, crescentic, and irregularly polygonal and other angular forms, as originally figured on page 329 of the ' London and Edinburgh Philosophical Magazine,' Nov. 1840 ; but with these are mixed a few red corpuscles of the usual circularity, which only were measured for the Tables. Size of the corpuscles.-They are the smallest in the vertebrate subkingdom ; and the smallest of all occur in the Ruminants (figs. 29- 34), especially in the Tragulidse (figs. 29-31) ; and thus this family may be distinguished from all other Vertebrates, not even excepting Moschus (Proc. Zool. Soc, Feb. 10, 1870, fig. 2), which was formerly confounded with Tragulus, and of which the anatomy has been described by Professor Flower in the 'Proc. Zool. Soc' March 16, 1875. Comparative views of the corpuscles of these two genera are engraved to a scale in the same ' Proceedings,' Feb. 10,1870. Since then, using Powell and Lealand's y1^ objective, I could detect no difference between these red blood-corpuscles oi Moschus moschiferus and Cervus nemorivagus (fig. 32), while the comparative smallness of those of Tragulus (figs. 29-31) was remarkable and significant. The largest corpuscles in the class belong to the Elephants (fig. 23), great Edentates (fig. 47), and pinniped Fera? (fig. 14); in some of which, as the Walrus (fig. 14), the Elephants (fig. 23), the Great Anteater (fig. 47), the Two-toed Sloth (fig. 48), and the Ardvark (Proc. Zool. Soc, Feb. 10, 1870, fig. 4), the corpuscles are as large as in a few Birds (figs. 6 J and 66). The Monotremata (fig. 52), Marsupialia (figs. 50 and 51), and Rodentia (figs. 43-46) have some-what large corpuscles, which in some Cetacea (fig. 20) are larger. Sometimes two sets of corpuscles occur in nearly equal proportions, one set about a third smaller than the other; this fact, though rare in most mammals, is not uncommon in the Squirrels. Of the Pachy-dermata the Elephants alone have the corpuscles larger than those of Man, and the smallest occur in the Horse (fig. 2 6 ) ; their comparative largeness in such a small species as Hyrax (fig. 28) proclaims it, though arranged here, but an irregular member of this order. In the Ferae or Carnivora there are great irregularities: while some of the largest apyrensematous corpuscles occur in this order, they are in many of its species smaller than in several Ruminantia. The families of Carnivora, according to the sizes of their red blood-corpuscles, would stand thus :-Seals (fig. 14), Dogs (fig. 15), Bears (fig. 11), Weasels (fig. 16), Cats (fig. 17), Viverras, Paradoxures (figs. 18 and 19). These sizes differ so much that by them alone Seals or Dogs may be easily distinguished from Viverras or Paradoxures ; while the same kind of diagnosis would be difficult, unless under the most favourable circumstances, and in some cases impos- |
