Gl 



If I may be permitted to express my own opinion on a subject 

 of considerable difficulty, and which certainly admits of much 

 doubt — although the difficulty proceeds entirely from the paucity 

 of species known, — I confess that I think the affinities of car- 

 nivorous Getacea among themselves would be still better expressed 

 by placing all the living species that are known in the two 

 following groups : — Baloenice and Delpliinidce. "We may then 

 make the sperm whales — animals, which, as we have shown, differ 

 in no important particular from dolphins — fall into the series of 

 Delpliinidce. 



But in order to understand this matter more .clearly, we had 

 better consider the place which the order of Getacea holds in the 

 class of Mammalia. This order is distinguished neatly from all 

 other mammals by the absence of hinder feet ; and the typical 

 Gatacea are evidently those which, in other respects, differ the 

 most in structure from the other orders of Mammalia. Now, 

 one of the characters most prevalent in these other orders is the 

 possession of molar teeth implanted in the maxillaries. Incisors 

 or intermaxillary teeth are often wanting, but, except in a few 

 Edentata, which are destitute of all teeth, the maxillary bones 

 are always provided with molars. Let us ask ourselves, then, 

 what Getacea are least oceanic in general structure, and, at the 

 same time, in the possession of molars ? The answer at once 

 will be, the herbivorous group. The existing herbivorous Getacea, 

 together with the extinct genus Zeuglodon, and perhaj)s another 

 fossil genus, form, without doubt, the aberrant group of the 

 order, and are all distinguished by the possession of molar teeth 

 with double roots, as distinct from their incisors. The remaining 

 Getacea, forming the normal group of the order, have no such 

 molar teeth. These may be divided into 1st, true whales, 

 Salcenidce, or those Getacea which have no teeth, but more or less 

 baleen instead ; and, 2ndly, dolphins, or DelpJiinidce, which have 

 only conical teeth with single roots, and more or less hollow, like 

 those of crocodiles. Now, this last group, or the family Del- 

 phinidce, may be divided into sub-families, as follows : — The genus 

 Inia of D'Orbigny, serving to connect the Flatanistina with the 

 Delphinina. 



