COPEIA 63 



In Mustclus henlei the sides of the mandible are 

 slightly convex; in Mustelus californicus they are 

 concave. 



One may appreciate with the naked eye that the 

 teeth of Mustclus henlei are somewhat sharper. With 

 the aid of a lens, a slight basal cup may be seen on 

 each side of most of the middle upper teeth, and on 

 the outer side of the lateral upper teeth. These are 

 scarcely developed on the lower teeth. In Mustelus 

 californicus the teeth are smooth, blunt, and not at 

 all cusped. 



In Mustelus henlei each scale on the side of the 

 body has a projecting spine at the tip, while at each 

 side of it is a small basal spine. That is, the scale 

 is tricuspid. In Mustelus californicus the edge of the 

 scale is entire. A strong lens is necessary to show 

 these characters. 



Mustelus lunulatus, with which Mustelus cali- 

 fornicus intermingles along the Lower California 

 coast, has the fins much as in Mustelus henlei, and 

 the teeth and mandible contour as in Mustelus cali- 

 fornicus. It may be known from them at once by 

 the lower lobe of the caudal projecting in a rather 

 sharp angle. In the other two species the posterior 

 edge of the caudal below the notch is regularly con- 

 cave without the lower lobe being produced. 



My material was: 



Mustclus henlei. Three specimens from San 

 Francisco, 15 to 26 inches long. 



Mustelus californicus. Six specimens from 23 

 to 32 inches long. Four of them from San Diego, 

 one from F.nsenada, Lower California, and one from 

 Magdalena Bay, L. C. 



Mustelus lunulatus. Three specimens from 19 

 to 25 inches in length. One from Mazatlan, Mexico, 

 and two from Panama. 



FnwiN Chapin Stakks, 

 Stanford University, Col. 



