442 Memoir Sears Foundation for Marine Research 



averaging a little shorter than diameter of eye; fifth gill openings only about ^s as long 

 as first to fourth; distance between inner ends of first gills about twice as great as di- 

 stance between exposed nostrils; distance between inner ends of fifth gills about half 

 (47—57 "/o) as great as distance between first gills. Free posterior margin of joint nasal 

 curtain nearly straight, coarsely fringed with short rounded lobelets. Mouth nearly 

 straight transversely, occupying about half of breadth of head. Floor of mouth, poste- 

 rior to dental plate, with 5—6 blunt fleshy papillae; transverse curtain on roof of mouth 

 with fringed margin. 



Teeth normally in seven series both above and below, but occasional specimens 

 with more or fewer; hexagonal; similar in general shape in the two jaws, but uppers 

 weakly concave anteriorly and lowers nearly straight; those of median row about 3.5 

 times as broad (transversely) as long (anteroposteriorly) in upper jaw and 2.5 times as 

 broad as long in lower jaw of young specimens, but increasing in relative breadth to 

 about five times as broad (transversely) as long (anteroposteriorly) in both jaws of large 

 individuals; teeth of the three lateral series on either side only about as broad as long; 

 length of median teeth about ^/g as great as horizontal diameter of eye; about four rows 

 of teeth exposed (i. e., in function) above and six below in small specimens, but about 

 six rows exposed above (5—6 others concealed in roof of mouth) and 12 — 13 rows exposed 

 below in adults. 



Subrostral fin broadly rounded in females but more ovate in general form in adult 

 males, its midpoint marked by a low protuberance. Minimum width of lateral continu- 

 ation of pectoral along side of head about V6~V4 ^^ great (opposite eye) as length of 

 subrostral fin, thus averaging narrower than in M. goodei. Dorsal fin about half as high 

 as the length of its base, its origin varying from about opposite rear tips of pelvics to 

 posterior to them by a distance about 1/3 as long as base of dorsal ; anterior margin of 

 dorsal nearly straight; posterior margin moderately convex toward apex but conspicu- 

 ously indented toward base; its base about equal to distance between exposed nostrils. 

 Pelvics extending rearward beyond rear levels of pectorals for a distance about half as 

 great as distance between eyes, or a little more; with abruptly rounded corners and nearly 

 straight margins; the distal margin weakly scalloped corresponding to its supporting 

 cartilaginous rays; anterior margin about 90 "/(, as long as distance from pelvic origin to 

 inner rear corner. Claspers of mature male moderately stout, cylindrical, reaching rear- 

 ward as far as first dorsal, perhaps beyond it; their tips simple, without terminal spines 

 or other rigid projections. 



Color. Greyish, reddish chocolate, or dusky brown above, the edges of the disc 

 paler; dorsal fin either of same hue as disc or pale greyish; tail either uniform brown or 

 dusky throughout its length, or palest toward base but darkening to nearly black toward 

 tip; tubercles above eyes of males described as either whitish or dusky. Lower surface 

 either pure white or whitish tinged with hue of upper surface, the pectorals dusky 

 toward their tips. Iris described as slaty brown, the pupil ringed with black. Teeth green 

 in all specimens seen by us. 



Relationship to Extralimital Species. The chief differences between M. freminvillii of 



