NO. 8 INTERRELATIONSHIPS OF THE CETACEA WIXGE 8/ 



the '" Dclphinincc." That which is known of it is an imperfect piece 

 of a braincase and a few other parts. The characters, so far as they 

 go, agree well with the ordinary dolphin type ; the feature which 

 especially distinguishes it is that the maxillary posteriorly is bowed 

 inward unusually strongly behind the nasal. In this respect, how- 

 ever, dolphins show great variation. The more exact position of the 

 genus cannot be determined. 



Phocanoidcs is established by Roy Andrews (1911, /. c) to include 

 two recent species, one a new species. Ph. truci from Japan, the other 

 a species which True had called PJiocccna dalli, likewise from the 

 northern part of the Pacific Ocean. The deviations from typical 

 Phoccrna are very small ; perhaps the most noticeable is that the teeth 

 are smaller, with the fan-like widening of the crown less pronounced. 

 There can scarcely be sufficient ground for generic separation. 



Xiphiodclphis {" ZipliiodclpJiis") (see especially Bassani e ]^Iisuri 

 and Dal Piaz, 1912, /. c.) is established on fragments of skulls from 

 Tertiary Italian deposits. There can be no douht that it is a near 

 relative of Schi::odclphis, etc., but its more exact position is not yet 

 clear. 



DelpJiinaz'us is established by Lull (1914, /. c.) on an imperfect 

 and compressed, indistinct skeleton from a no doubt Miocene deposit 

 in California. The genus is supposed to stand very near to Delphinus 

 in the narrow sense. The form of the palate, however, the only- 

 character that distinguishes Delphinus from nearly related Delphinids, 

 does not seem to have been ascertained. One of the most important 

 peculiarities is that the atlas and axis are mutually free. According 

 to what is known it is not possible to clear up the relationship of the 

 genus to other Delphinids ; but it ought to be especially compared 

 with Heterodelphis. 



'^ (P. 38.) It is Flower who has especially emphasized the differ- 

 ence between Delphinids and Physeterids with regard to the relation- 

 ship of the hindmost ribs to the vertebrae. It is likewise he, in his 

 paper on Inia (Trans. Zool. Soc. London, vol. 6, 1869. pp. 98-100) 

 and elsewhere, who has pointed out the intermediate position of the 

 Platanistids. The question about the interpretation of the transverse 

 processes, etc., had previously been discussed, among others by Esch- 

 richt in his paper on Plafanista (1851, pp. 369-370). Later it has 

 been extensively dealt with by Gerstaecker (Das Skelet des Doglings, 

 Hyperoodon rostratus, etc., 1887) and it is also taken up by Abel 

 (Sitzungsber k. Akad. Wissensch. Wien, math.-naturwiss. Kl., vol. 

 118, pt. I, 1909, pp. 247-249). 



