108 PROCEEDINGS OF UNITED .STATES NATIONAL MUSEUM. 



on the outer margin towards the base of the tooth. Upper jaw with a 

 moderate, trianguUir median tooth, denticuhited like the others. 



Lower teeth very different in form, long, slender, sharp, straight, sub- 

 terete, rising from broad roots, somewhat turned outward, but more 

 erect than the upper teeth. jS'o distinct notch on outer margin, where 

 a slightly obtuse angle is formed. Edges of lower teeth everywhere 

 strictly entire. 



Its relations seem to be, so far as can be judged by the teeth, with such 

 species as Carcharias fjutjot Bleeker and G. menisorrali Val., members 

 of the "genus" Phitypodon Gill. 



Mustelus lunulatus, ap. nov. (29211.) 



Allied to Mustelus cams (Mitch.) Dek. 



Body elongate ; the back little elevated. Head depressed, rather long 

 and pointed ; length of snout from mouth about one-sixth more than the 

 distance between angles of mouth, and nearly twice the length of the 

 mouth, from a line connecting the angles, to the chin. Eye oblong, 

 large, a little nearer angle of mouth than nostril; distance from eye to 

 nostril three-fifths distance from nostril to tip of snout, Interorbital 

 space narrow, 24 times in distance from snout to first gill-opening, some- 

 what less than Jength of snout as measured from eye. Angle of mouth 

 with a pit from which furrows extend on each lip for a short distance, 

 about equal on each lip and considerably less than length of nostril. 

 Nostrils inferior, large, their length a little more than half eye and nearly 

 half their distance from eye ; the anterior flap large; posterior flap turned 

 inward, half as long as eye. Distance between nostrils 3 iu snout as 

 measured from eye. 



Teeth, as in M. cauls, paved ; some of tlieinner teeth somewhat pointed ; 

 spiracles small, but evident ; head without conspicuous mucous pores. 

 Gill-openings small, the last two above base of pectoral, the depth of 

 the middle one about equal to the length of the eye, and less than the 

 length of the branchial area. 



All the fins with their free margin notably lunate or concave. Inser- 

 tion of first dorsal well behind pectorals, and nearly opposite the tip of 

 the inner lobe of the latter, the outer lobe extending about to the mid- 

 dle of the fin ; distance of insertion of first dorsal from anterior root of 

 pectorals about ^ its distance from tip of snout. First dorsal high, its 

 anterior lobe when depressed reaching a little past tip of posterior lobe. 

 .Length of base of first dorsal about equal to its vertical height, and 

 nearly half greater than interorbital width. Distance between dorsals 

 2f times base of first and a little more tluiTi 3 times base of second. 

 Posterior angle of dorsal produced but not reaching to vertical from 

 front of ventrals. Middle of dorsal nearer pectoral base than ventral 

 base by a distance nearly equal to the diameter of the eye. 



Second dorsal not very small, proportionately lower than first, its 



