SQUALUS ACANTHIAS. 193 



GiJNTH., 1870, Cat. fishes Brit, mus., 8, p. 418; Canestrini, 1872, Ital. pesci, p. 39; Malm, 1877, 

 Goteb. och Bohus. fauna, p. 624; Gerv. & Boul., 1877, Poiss. Fr., 3, p. 20G, 207, pi. 79; Moreau, 

 1881, Poiss. France, 1, p. 342; Doderlein, 1881, Man. ittiol. Medit.. 2, p. 86; McCoy, 1883, 

 Zool. Vict., pi. 75; Day, 1884, Brit, fishes, 2, p. 315, pi. 160, f. 2. 



Squalus (Acanthorhinus) acanthias Blainv., 1830, Poiss. Fr., p. 57. 



Squalus (Spinax) acanthias Voigt, 1832, Thierreich, 2, p. 510. 



Acanthias acanthias Bonaparte, 1839, Mem. Soc. sci. Neuch., 2, p. 8 extra. 



Acanthias americamis Storer, 1846, Mem. Amer. acad., new ser., 2, p. 254; Gill, 1861, Proc. Acad, 

 nat. sci. Phil, p. 60 extra; Storer, 1867, Mass. fish, p. 256, pi. 38, f. 1. 



Acanthias sp. Richardson, 1848, Erebus & Terror, Fish, p. 44, pi. 28, f. 1-2. 



Squalus americanus Gill, 1864, Proc. Acad. nat. sci. Phil., p. 263. 



? Acanthias lebruni Vaillant, 1888, Cap. Horn Poissona, p. 13, pi. 1, f. 2. 



Head one fifth of the total length, depressed. Snout tapering, nearly half 

 as long as the head, blunted at the end; nostrils little nearer to the end than to 

 the mouth, anterior valve short, longer and forming a sharp angle at the outer 

 edge, hardly notched in the middle, where the process is rudimentary or absent. 

 Orbit little farther from the first gill opening than from the end of the snout, 

 length two fifths of that of the snout, little more than the internarial width, 

 rounded in front. Mouth with a short deep groove and with labial folds at each 

 angle, width two thirds of the preoral length. Teeth with cutting edges nearly 

 transverse, upper narrower and little more oblique. Spiracle moderate, one 

 diameter farther back than the eye, opening upward. Width of gill openings 

 about half the length of the orbit, fifth widest, in front of the pectoral. Pectorals 

 subtriangular, broader than long, hind margin slightly concave, hind angles 

 rounded, fin applied to the side hardly reaching behind the dorsal spine. Spine 

 of the first dorsal on a vertical one length of the orbit farther back than the inner 

 angle of the pectoral, length less than half the height of the fin; hind margin 

 of fin slightly concave, hind angle produced, base less than height of fin, one 

 fifth of the distance from the second dorsal, little more than one third of the 

 distance between the bases of second dorsal and caudal. Base of second dorsal 

 more than two thirds as long as that of the first dorsal; spine longer than that 

 of the first, nearly as high as the fin; hind margin of fin concave, upper angle 

 rounded, hinder produced. A rudimentary dermal fold on each side of the tail 

 opposite the hinder half of the space between the second dorsal and the caudal. 

 Caudal twice as long as deep, subcaudal lobe produced, hinder margin of sub- 

 caudal and terminal broadly rounded to the blunted extremity. Ventral origins 

 about midway from those of the pectorals to the origin of the caudal, much 

 nearer to the origin of the second dorsal than to that of the first dorsal. 



Back brown; lower surfaces white; with two series of white spots on each 

 flank, varying in numbers and shapes; commonly there is a pair near the front 

 of each dorsal and another behind, and those of the lower series are much elongate. 



