so SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



attention to the fact that there is no reason to regard the structure of 

 the rostrum in Eurhinodclphis as different from that in any other long- 

 beaked porpoise, at least so far as regards the specimen collected by 

 True near Chesapeake Beach, Maryland, and briefly recorded in 1908 

 (Proc, Amer. Philos. Soc, Vol. 47, p. 388). This skull (No. 10,464, 

 U. S. National Museum), well preserved except for the base and 

 sides of the braincase, agrees in all essential respects with Abel's 

 figures (Mem. Mus. roy. Hist. Nat. Belgique, Vol. i, pis. 6-8, 1901) 

 of the European animal. The structure of the rostrum is not very 

 different from that of the rostrum of Stcnodclphis. As is commonly 

 the case in long-beaked dolphins the boundaries between the maxil- 

 lary and intermaxillary bones are obliterated. Obliquely crossing 

 the side of the rostrum, from the main lateral sulcus to the alveolar 

 level, in the position marked by the white suture line in Abel's plates 

 there occurs a faint groove about 3 mm. wide and so shallow as to 

 be almost invisible in unfavorable light. It appears to indicate the 

 course of some nerve or blood vessel that ran forward and down- 

 ward along the surface of the maxillary from the lateral sulcus to the 

 anterior part of the roof of the mouth. There is nothing in the 

 appearance of this shallow, wide groove that suggests the narrow, 

 smooth suture which joins the maxillary and intermaxillary in the 

 skulls of porpoises which retain traces of this juncture. If the char- 

 acters of the European specimens are no more unusual than those 

 of this Maryland skull there would appear to be no grounds for 

 regarding Eurhinodclphis as the representative of a distinct group. 

 Stcnodclphmincc. — The genus Stenodclphis has been placed in the 

 Dclphinidcc, the " Plafanistidcc " and the Iniidcc. The position which 

 it seems to occupy most naturally is that of a subfamily in the 

 family DelpJiinidce. With it should be associated the extinct Palcco- 

 pontoporia and perhaps Argyrocctus. The characters of the group 

 are to be found in the structure, of the braincase, the temporal fossa, 

 and the pterygoid, not in the elongated beak. The pterygoid is widely 

 spread over the surface of the alisphenoid, completely covering this 

 bone and coming into broad contact with the frontal as in Dclphin- 

 ap ferns. The external reduplication of the pterygoid is like that of 

 Dclphinaptcrns, but even better developed ; the internal reduplication 

 is large and apparently of the same type as in the true dolphins, but 

 the only specimen which I have examined is not in entirely satis- 

 factory condition. Orbits relatively smaller than in the Delphinhicc, 

 their position immediately in front of the transverse plane occupied 

 by the narial passages ; these peculiarities agreeing with the condi- 



