400 G. h\ Eastman — New Elasmobranchs from. Solenhofen. 



belonging to the Carnegie Museum, but rather to signalize the 

 characters of a few new or little known forms, reserving more 

 detailed descriptions and a review of the entire Upper Juras- 

 sic piscine fauna until some later season. The species to 

 which special attention is directed are referable to four genera, 

 as follows : Cestracion, Phorcynus, Squatina and Rhinobatus. 



Family Cestraciontid^e. 



Genus Cestracion Cuvier. 



To this existing genus, commonly known as the Port Jack- 

 son shark, have been referred certain skeletal remains not as 

 yet satisfactorily distinguished from it which occur in the 

 Lithographic limestone of Bavaria. The holotype of the 

 so-called " Acrodus faloifer" ( '= Cestracion) of Wagner is pre- 

 served in the Palaeontological Museum at Munich, and other 

 imperfect portions of the skeleton are to be seen in the collec- 

 tions of the British Museum. None, however, exhibits the 

 body outline and fin-characters at all satisfactorily. 



Cestracion falcifer Wagner. 



(For reference to literature see Woodward's Cat. Fossil 

 Fishes British Museum, 1889, pt. 1, p. 332.) 



The typical example of this species shows every indication 

 of being an adult individual, and is estimated to have had a 

 total length of about 4-0 cm . In it the two dorsal fin-spines are 

 seen to be of unequal size, both are gently recurved, and the one 

 in advance of the anterior dorsal is inserted at a point about 

 midway between the pectoral arch and the origin of the pos- 

 terior dorsal fin. It would appear from the published fig- 

 ures, also, that the pelvic fins arise opposite the first dorsal, and 

 the shagreen granules are described by von Zittel as "schau- 

 felformige oder kornelige," without being markedly differen- 

 tiated in size. To this species has also been referred by von 

 Zittel (Handb. Palseont. vol. 3, p. 77) a smaller but better 

 preserved individual, having a total length of only V2-5 C "\ or 

 less than one third as large as the type. According to the 

 author just named, the smaller specimen, which he regards as 

 the young of C. falcifer, has feebly striated lateral teeth, and 

 is provided with enlarged stellate tubercles in the dorsal region. 

 The description of this feature reads : " Neben den schaufel- 

 f ormig gestalteten Chagrinschuppen liegen in der Riickenregion 

 knrze gekrummte Stacheln, welche sich auf einer vierstrah- 

 ligen Basis erheben." 



It cannot escape notice that the smaller example just referred 

 to presents characters in common with the well preserved 



