398 MEMOIRS OF THE CARNEGIE MUSEUM. 



The close resemblance between the genus and species under consideration and 

 the form described by Wagner as Paloeoscyllium formosum, from the Kimmeridgian 

 of Solenhofen, appears to have been overlooked by students of fossil fishes gener- 

 ally. This inadvertence is perhaps attributable, however, to the imperfect con- 

 dition of the type-specimen which served for Thioiliere's description, although in 

 the text it is stated that the anal fin has not been preserved, and the outlines of 

 all the others are indicated merely by a slight discoloration of the matrix. "Le 

 contour du corps et de toutes les nageoires est indique seulement par la coloration 

 differente de la pierre, et le relief n'est sensible que pour la colonne dorsale" 

 {I. c, p. 10). Judging from the published figure, the fin, which Thiolliere interprets 

 as one of the pelvics, is more properly to be regarded as a displaced pectoral belonging 

 to the opposite side of the body. If a pelvic, it must have been displaced forwards. 



Genus Palceoscyllium Wagner. 



"First dorsal fin above or partly behind the pelvics; origin of second dorsal 

 in advance of the anal, which is small. Tail of moderate length."^ Teeth minute, 

 with at least one pair of lateral cusps. 



4. Palaeoscyllium formosum Wagner. 



(For synonymy cf. A. S. Woodward, Cat. Foss. Fishes Brit. Mus., Pt. I, p. 338.) 

 This species, which is the type of the genus, attains a length of about 40 cm. 

 Pectoral fins large, in form resembling those of the existing Scyllium. Pelvic fins 

 completely beneath the first dorsal; anal fin beneath the hinder portion of the 

 second dorsal. Vertebral column composed of about one hundred asterospondylic 

 centra. 



Known only by the original of Wagner's figure and description, this species 

 is worthy of notice in this connection on account of its close affinity to the pre- 

 ceding genus. The Cretaceous Thyellina of Agassiz is also a near ally. 



Suborder BATOIDEI. 



Family SQUATINID^. 



Genus Squatina Dumeril. 



All known fossil Squatinidse exhibit the characters of this, the single surviving 



genus, and are consequently referred to it. The earliest species are of Upper 



Jurassic age. They resemble sharks in having lateral gill-clefts, but agree with 



Rhinobatus in the forward extension and lateral expansion of the pectoral fins; 



« A. S. Woodward, Cat. Foss. Fishes, Vol. I, p. 338. 



