28 DEEP SEA FISHES. 



fit the depth of two hundred fathoms or more." The greatest depth noticed 

 for any of the species of Squahis is that by Vinciguerra, of three hundred 

 and twenty-eight fathoms for ^S'. uyatus Raf in the Mediterranean. 



Centroscyllium nigrum sp- "• 



Plate I., fig. 2 ; Plate IV. and T'., Anatomy ; Plate LXIX., fig. 1, Lat. Sijst. 



The proportions and shape of this species are similar to those of Cciitro- 

 scyUiimi Fubncii Reinh., or of C. granulutum Glint. The iy^Q is moderately 

 slender and elongate, and is compressed behind the shoulders ; the body 

 cavity occupies about three fifths of the entire length. Head large, broad, 

 depressed, inclusive of the gill openings little more than one fourth of the 

 total. Snout broad, in length nearly equal to the width of the forehead, 

 broadly rounded across the front. Nostrils at the edge of the snout, nearer 

 to the end than to the eye. Eye large, lateral, without a nictitating mem- 

 bi'ane ; orbit with a more distinct angle on the back than on the front 

 border. Mouth wide, inferior, curving forward moderately in the middle, 

 where it extends but little forward of a line joining the hind borders of the 

 orbits, with a short groove around each angle, from which another groove 

 continues backward nearly half-way to the first gill opening. Teeth small, 

 numerous ; upper with tliree erect, slender, acuminate cusps, median cusp 

 largest, and outer cusps each with a rudimentary cusp on the outer side ; 

 lower with five similar cusps, median largest, and outer two small, Plate IV., 

 fig. 5, C. Gill apertures five, hardly as wide as the eye, posterior two of 

 each side closer together and near the base of the pectoral. Spiracles 

 mediuHj, superior, transversely crescent-shaped. Rostral ampullte numer- 

 ous, Plate IV., fig. 3, those of the top of the head numbering a hundred, 

 more or less, and those below the snout nearly twice as many. 



In the skull, Plate IV., fig. 1, 2, and Plate V., fig. 1, the affinities of this 

 shark to Squalus acantliias Linn., to Ehnoj^terus spinax Linn., and to Ccntro- 

 phorus granulosus Bl. Schn. and their allies are very apparent. The entire 

 skull is shorter and broader and the rostral cartilage is broader and shorter 

 than in eitlier of the mentioned forms. The width across the olfactory 

 capsules is considerably greater, but the post-orbital processes are nearly 

 of the proportions of those of C. granulosus. Above the symphysis of 

 the upper jaws on the lower side of the skull there is a slender process, 

 IMates IV. and V., fig. 1. At each side of the mouth there are three 



