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Show 504 PROF. FLOWER ON THE DELPH INI DJ5. [NoV. 20, 10 and 11. ussumier, Gervais in the 'Osteographie des Cetaces,' pl. xxxix. figs. 1 The specimen is from the Malabar coast, and marked " D 1827," but does not appear to have been described until the publication of the ' Osteographie.' It is certainly not the D. longirostris ot Gray's 'Spicilegia,' p. 1 (1828), described from a skull now in the Leiden Museum, as that has fewer teeth and no grooves on the palate, and is therefore not a true Delphinus, although, as said above, Gray in his Catalogue and Synopsis places it at the head of the section of Dolphins characterized'by the " Palate with a deep groove on each side," and joins the Paris specimen with it in his account of the species. It may be convenient to append a Synopsis of the principal characters of the divisions of the whole family, which appear to me of generic value, with some remarks upon the best-known species. This will serve to show what are the natural groups into which the different members of which it is composed appear, according to our present knowledge, to resolve themselves, although in endeavouring to set it out, the usual difficulty has occurred in arranging in a linear series a number of forms the affinities of which are so closely intertwined. Although the most nearly allied have been brought together when possible, this cannot always be done in such a list. The arrangement must therefore be considered to a certain extent arbitrary, and subject to modification according to the judgment of different zoologists. Even in the primary grouping together of the Dolphins with rounded heads and those with projecting beaks I have probably followed too much the traditional and artificial order, instead of finding one more consonant with natural affinities. W e must wait until our Museums are more abundantly supplied with specimens before it will be possible to attempt with any success a complete and critical examination of the minor modifications which we commonly call specific. Synopsis of the Genera of DELPHINID.E. A. With rounded head, without distinct rostrum or beak. In the skull the rostrum is about equal in length to the cranial portion. a. The first and second cervical vertebrae not united. MONODON, Linnaeus, Syst. Nat. ed. 12, i. p. 105 (1766). Pterygoid bones very small, not meeting in the middle line, approaching each other posteriorly as in Delphinapterus (see fig. 3, p. 472). Dentition reduced to a single pair of teeth, which lie horizontally in the maxilla?, and which in the female remain permanently concealed in the alveolus, while in the male the right tooth usually remains similarly concealed and abortive and the left is immensely developed, attaining a length equal to more than half that of the entire animal. Vertebrae : C. 7, D. 11, L. 6, C. 26 ; total 50 **. Cervical region comparatively long, and all the 1 The numbers of the vertebra? and of the teeth given in this synopsis are averages, subject to slight individual modifications. |
