GALEORHINUS. 169 



Back uniform greyish brown; lower surfaces whitish. 



Total length L'ii, snout to abdominal pores 12, snout to hindmost gill opening 

 5, snout to mouth 1§, and caudal 5§ inches. 



Specimens described from San Francisco, ( !al., collected by Alexander Agassiz 

 and Thomas G. Cary. 



Galeorhinus. 



Mustdus Valmont, 1768; Linck, 1790; Cuvier, 1817. 



Galeorhinus Blainv., 1S16, Bull. Soc. philom., p. 121, 1830, Poiss. Fr., p. 81 (part). 



Pleuracromylon Gill, 1S64, Proc. Acad. nat. sci. Phil., p. US (name). 



Cynias Gill, 1903, Proc. U. S. nat. mus., 26, p. 960 (nainc). 



Body and tail nearly equal in length. Head short, broad, depressed, taper- 

 ing anteriorly, broader and flattened below. Snout produced, rounded on the 

 end. Eyes lateral, lower lid with a nictitating fold. Nostrils large, far apart, 

 without a nasoral groove; anterior valve produced in its outer angle. Spiracles 

 small, behind the eye. Mouth subangular, rounded anteriorly; labial fold well 

 developed. Teeth small, numerous, in pavement, smooth or with shallow 

 notches or low cusps. Dorsals similar in shape, first above the abdomen, second 

 above the anal. Tail without pits; caudal fins not deep; subcaudal followed 

 by a notch, lobe feebly developed. 



G. stefanii Lawley is from the Pliocene of Tuscany. 



When all of the species of this genus are better known it may be that they 

 can be arranged according to the presence or absence of a placental attachment 

 for the young. At present it is known that in G. stellatus, and G. manazo this 

 attachment is absent, that it obtains in G. laevis, G. calif ornicus, and G. dorsalis, 

 and that in G. antarclicus the young are developed in compartments, formed 

 around each of them in the oviducts, according to Parker, 1882, 1890, or on a 

 placental attachment according to Waite, 1909. Apparently the species with 

 the smoother teeth are those without the placenta, while, on the other hand, those 

 with teeth approaching the cuspidate forms in species of Triakis are those that 

 possess it. See Plate 60, f. 1-4 and explanation. 



Commonly spotted with white 



dorsal origin near the axil of the pectoral 

 teeth without notches 



upper labial fold longer . . . mustelus (page 170) 

 dorsal origin above the inner angle of the pectoral 



teeth with a shallow undulation on the hinder edge 



upper labial fold longer .... manazo (page 171) 



