196 [NOVEMBEK; 



Characteristics of some Cartilaginous Fishes of the Pacific coast of North 



America. 



By Charles Girartj. 



1. Cestracjon francisci, G. The largest of these specimens now before us, 

 and measuring nearly two feet, bears a very strong resemblance to C. Phillippiy 

 though of a somewhat more bulky appearance. The bony ridge, above the eye, 

 is much more developed, and the fins are larger also. The posterior margin 

 of the caudal is bilobed instead of being rounded : an emareination correspond- 

 ing to the top of the vertebral column. The anal is placed farther back ; its tip 

 projecting beyond the anterior margin of the inferior lobe of the caudal. The 

 posterior extremity of the ventrals extends beyond the anterior margin of the 

 second dorsal. Color, above yellowish grey, darker in the young; beneath light 

 yellow. Small roundish black spots are spread all over the body and fins. 



Collected by Lt. W. P. Trowbridge, U. S. A., in the Bay of Monterey, Cal. 



2. Triakis semifasciatum, G. This species is closely allied to T. scyllhim, 

 from which it differs by a more backward position of the mouth or else a more 

 developed snout. The chagrin which covers the surface of the skin is more * 

 acute, giving to the fish a more prickly aspect. Color above olivaceous grey, 

 lighter beneath ; yellowish under the head and throat. Dorsal region marked 

 by transverse bands of deep black, with spots of the same hue between the bands, 

 and also beneath them, along the sides of the body. A black spot exists at the 

 base and upper surface of the ventrals and pectorals. The caudal is spotted all 

 over, whilst the dorsals and anal are so only at their base. 



Specimens were collected near Presidio, in the Bay of San Francisco, Cal., by 

 Lt. W. P. Trowbridge, U. S. A. 



3. Spinax (Acanthias) suckleyi, G. Specimens about twenty nine inches 

 long. Snout very much flattened, elongated, and subconical in its outline when 

 viewed from above. Eyes very large, elongated and placed immediately in ad- 

 vance of the mouth. Five branchial apertures well developed. Mouth large. 

 Dorsal fins moderate ; spine of anterior dorsal rather small. Pectorals very 

 large and expanded, concave upon their posterior margin. External margin of 

 ventrals rounded. Inferior lobe of caudal deeply emarginated ; upper lobe long 

 and lanceolated. Color above of a dark grey with a few small whitish spots; 

 beneath, under the head and belly, dull yellowish ; farther back, of a light 

 greyish hue. 



Collected at Fort Steilacoom, Puget Sound, W. T., by Dr. Geo. Suckley, 

 U. S. A. 



4. Rhinobattjs producta, Ayres, in Proc Cal. Acad. Sc. I. 1854. A male 

 specimen, thirty eight inches in total length, brought this species to our know- 

 ledge. The rostral distance, from the eyes forwards, is of a much lighter hue 

 than the* rest of the body. A blackish band exists along the middle of the back, 

 with diffused blotches upon the sides, and a double band of the same color along 

 the middle of the snout. 



Collected either at Presidio or Monterey, Cal., by Lt. W. P. Trowbridge, 

 U. S. A. 



5. Raja binoculata, G. Transverse diameter, from tip of one pectoral fin 

 to the other, greater than the longitudinal, from tip of snout to the extremities 

 of the ventrals. Snout tapering and rounded anteriorly. Eyes moderate ; orbit 

 surrounded with spines. A spine upon the dorsal line, near the origin of the 

 trunk. Tail longer than the body and head together, slender and flattened most 

 of its length ; provided above with a series of spines extending from its origin 

 to the base of the first dorsal fin. Second dorsal within a short space of the first 

 and approximating the tip of the tail. Ground color olivaceous brown ; snout 

 dull whitish. A large subcircular black ring at the base of pectorals enclosing 

 a large subcircular black spot. At a short distance behind these may be seen a 

 much smaller and more obsolete subcircular dark ring, clouded within with 



