96 THE PLAGIOSTOMIA. 



of the tail. Pectorals large, broad, rounded at the angles, reaching the ventrals, 

 which are much smaller. Claspers of the male round and thick. Vertebral 

 axis of the tail nearly straight. Subcaudal long, a notch between it and the 

 terminal. Anal long. Pectorals, ventrals, anal, and caudals have much the same 

 appearance as those of Apristurus indicus, being rather close together. 



The describers of this peculiar form have placed it in the Notidani between 

 Hexanchus and Chlamydoselachus as an archaic type of a new family of Diplo- 

 spondyli. This classification is undoubtedly due to misunderstanding, since 

 the form is not archaic, but one of the most differentiated, and is not at all nearly 

 allied to either Hexanchus or Chlamydoselachus as would be necessary to secure 

 it a position in their group of the Antacea. 



The type was about 20 inches in length, of a dark brown color, and was 

 taken in the Sea of Mindanao at a depth of 585 fathoms. 



Apristurus, gen. nov. 



Body about half of the total length. Snout elongate. Anterior nasal 

 valves separate from one another and from the mouth. Eye large. Spiracles 

 small, near the eye. Mouth large, with labial folds on both jaws. Teeth small, 

 three to five cusped. Gill openings small, hindmost above the pectoral. Dorsals 

 small, inserted behind the body cavity. Pectorals moderate. Ventrals, anal, 

 and subcaudal large, close together. Upper edge of the caudal not armed with 

 enlarged scales. Vertebral axis of the caudal not raised. Distinguished from 

 Pristiurus, the closest ally, by the larger and more closely placed lower fins and 

 by lack of the caudal armature, and from Catulus and its closer allies by the 

 elongate snout, the nasal valves, the lips, the labial folds, and the fins. Type 

 species Scylliorhinus indicus Brauer. 



Atlantic, Indian Ocean, Japan, and Eastern Pacific. 



Pectorals, ventrals, anal, and subcaudal large 



ventrals, anal, and subcaudal narrowly separated 

 dorsal origin on a vertical from the vent 



first dorsal the smaller . . . . indicus (page 97) 

 ventrals and anal farther apart; anal and subcaudal close together 

 dorsal origin above the hind ends of the ventral bases 



first dorsal about equal the second . macrorhynchus (page 97) 

 dorsal origin little in advance of the anal 



first dorsal base longer than second . platyrhynchus (page 98) 



