176 THE PLAGIOSTOMIA. 



Total length 37, snout to abdominal pores 17s, snout to fifth gill opening 7, 

 snout to mouth 2f, caudal 7| inches. 

 Melbourne. 



( Ialeorhinus laevis. 



Plate 4, fig. 6-9; Plate 60, fig. 1-4. 



Galeus laevis Rondelet, 1554, Pise, p. 375; Salvia.ni, 1554. Aquat., f. 137; Valmont, 1768, Diet. 



hist, nat., 2, p. 102; Duhamel, 1782, Traits, 4, sect. 9, p. 300. 

 Squalus mustelus Lixnk, 1758, Syst., 1, p. 235 (part); 1766, Syst. nat., 1, p. 400; Bonnateree, 1788, 



Ichth., p. 7, pi. 7, f. 21. 

 Squalus canis Mitch., 1815, N. Y. lit. & philos. trans., 1, p. 486. 

 Mustelus laevis Risso, 1826, Hist, nat., 3, Poissons, p. 127; Muller, 1842, Abh. Akad. wiss. Berlin, 



p. 187, pi. 3, f. 1; Muller & Henle, 1841, Plagios., p. 190, pi. 27, f. 2; Domeril, 1865, Elasm., 



p. 401, pi. 3, f. 4-6; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 385. 

 Squalus (Mustelus) laevis Voigt, 1832, Thierreich, 2, p. 508. 

 Mustelus equestris Bonaparte, 1841, I^on. Fauna Ital., Pesei, pi. 49 (132) f. 2. 

 Mustelus vulgaris Muller & Henle, 1841, Plagios., p. 64 (part). 

 Mustelus canis DeKay, 1842, N. Y. fish., p. 355, pi. 64, f. 209; Storer, 1867, Mass. fish., p. 251, pi. 37; 



f. 2; Poey, 1868, Repertorio, 2, p. 453; Jord. & Gilbert, 1882, Bull. 16, U. S. nat. mus., p. 870; 



Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 29. 

 Mustelus megalopterus Smith, 1849, Air. Pisces, pi. 2. 

 Pleuracromylon laevis Gill, 1864, Proc. Acad. nat. sci. Phil., p. 148. 

 Mustelus natalensis Steindachner, 1S66, Sitzb. Akad. wiss. Wien, 53, p. 482, pi. 1. 

 Mustelus hinnulus Jord. & Gilbert, 18S2, Bull. 16, U. S. nat. mus., p. 19. 

 Rhinolriaeis laeris Jord. & Gilbert, 1S82, Bull. 10, U. S. nat. mus., p. 60. 

 Cynias canis Ribeiro, 1907, Arch. Mus. nac, 14, p. 101, pi. 7. 



Trunk long, slender; body cavity less than half of the total length; head 

 narrow, depressed, flattened beneath; snout moderate, tapering, blunted at the 

 end, in length greater than the width of the mouth. Nostrils large, distant from 

 the mouth about half as far as from the end of the snout; anterior valve ending 

 in a produced rounded lobe. Mouth twice as wide as long, subangular in front; 

 labial folds well developed, less than half the length of the jaw, about equal. 

 Teeth small, in pavement; cusp short, angular, with a shallow notch on the 

 outer edge near the middle forming two denticles which vary in length and sharp- 

 ness with age, sex, position, and use. Eye with a nictitating fold; pupil horizon- 

 tally elongate; length of orbit nearly equal to the prenarial length of the snout, 

 or to half of the preoral length, greater than the width of the gill openings or the 

 length of the mouth. Fins concave on the hind margins. Pectorals two thirds 

 as broad as long, outer and inner margins convex, angles blunted, outer angle 

 less than 90°, inner greater, base narrow. Origin of dorsal little in advance of 

 the hind margins of the pectorals, behind the ends of the pectoral bases, length 

 of base nearly two and one third times in its distance from the second dorsal, 

 height less than three fourths of the base, hind angle not quite reaching a ver- 

 tical from the ventrals. Ventrals nearer to the first dorsal than to the second. 



