14 Field Columbian Mtseum — Geology, Vol. II. 



length. The neck in life must have been thick and heavy at the base, 

 tapering rapidly from the trunk to the head. The'trunk was broad, 

 as is evident from the position of the ribs, with the under side not flat, 

 as might be supposed, but strongly convex from side to side. The 

 abdominal region proper, between the girdles, must have been short, 

 and could not have been very distensible. The short tail was thick at its 

 base, as is conclusively shown by the attachment of the ilia and the 

 elongated ischia. Furthermore, the fore legs, at least, must have 

 been enclosed for a considerable distance at their attachment by the 

 skin and muscles of the pectoral region; they could not have been 

 pedunculated to the extent that they are usually represented to be in 

 the restorations. The species was named in honor of Prof. H. F. 

 Osborn of Columbia University. 



The distinguishing characters, both family and generic, may be 

 summed up as follows: 



Dolichorhynchops. — Head elongate, the facial 'region much attenuated; 

 teeth nearly uniform in size, small; prefrontal and post frontal bones not 

 joined; parietals extending into a high crest; sup/ aoeeipilal bones separated ; 

 internal nares small, included between the vomer and palatine only ; pala- 

 tines broadly separated throughout ; a large vacuity between the pterygoids 

 anteriorly; quadrate proeess of pterygoids short. Neek but little longer 

 than the head, eon/posed of nineteen or twenty vertebra'; all presacral 

 vertebra' of nearly equal length, moderately eoneave, and with vascular 

 foramina below; spines short, uniform in length; diapophyses of the dorsal 

 vertebra situated high up. Coraeoids with long epicoracoid process; 

 clavicles and seapuhe free; episternum with an emargi nation in front and 

 behind, the latter forming part of a large interclavicular foramen. 

 Three cpipodial bones, all broader than long. Ischium elongated, 

 length ten feet. 



Skull. — The skull of Dolichorhynchops osborni is of a remarkably 

 elongate and slender form, attenuated in front of the orbits, and with a 

 thin, high, parietal crest. The region between the eyes is very nar- 

 row, the superior temporal vacuities large, and the teeth numerous 

 and slender. The head is more nearly of the typical aquatic fish-eat- 

 ing type than is perhaps known in any other plesiosaur, and the neck 

 is as short as or shorter than in any other plesiosaur hitherto 

 described. The skull, as received, was lying partly upon its left side, 

 with a part of the right side separated and injured, some of the bones 

 having been macerated away. The specimen was completely removed 

 from the matrix, including even that which was between the bones, 

 and the elements of the brain case were separated out. In conse- 



