30 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



some of whicli are soinetime.s iiregnlarly crowdi'd to,t;etlier. Between the dorsals there are, 

 as a rule, few spines. The teetli form from fortyoue to forty-four series in the upper, and 

 from forty-one to forty-three in the lower Jaw. Coloration dark grayish brown above; the 

 mucous pores marked with black vermicuhir s|)ots. Lower surface blackish, without spots. 

 (Gunnini and Giinthcr.) 



Tiiis species is locally not uncommon ou the Norwegian coast; for instance in Throndhjem 

 Fjord, at a dci)th of l^O to 200 fatlioms. It is one of the larger skates, the specimens in the 

 British Museum measuring from 3S to 46 inches in width. 



Order HOLOCEPHALI. 



IMovepUdU, Mi'i.i.KR, Abhaiidl. Akad. VViss. Berlin, 1S34, 74.— GOnther, Cat. Fish. Brit. Mus., viii, 84«. 

 Holocephali, Gill, MS. 



Selachians distinguished by the confluence of the hyomandibular bone with the cranium, 

 tlie coalescence of the maxillary and palatine elements with the skull, tlie development of 

 a rudimentary operculum, and the existence of a single external gill opening on each side 

 behind the head. (GUI.) 



Family CHIM^ERID^E. 



Chimmidn; GC'NTHER, Cat. Fish. Biit. Mus., viii, 1870, 349. 



Body rather robust, elongate, tapering posteriorly. Head compressed. Mouth inferior. 

 Upper lip deeply notched. Nostrils confluent with the moutli, separated by a naiTow 

 isthmus. Jaws with the teeth confluent into four bony lamina^ above and two below. No 

 spiracles. Males usually with a cartilagiiKms hook on the upper part of the snout, armed 

 with prickles at the tip, and turned forward. Pectoral fins free, placed low. Ventral fins 

 abdominal, many-rayed, provided in the male witli claspers. Dorsal fin usually divided, 

 anteriorly with a very strong spine, which is grooved beliind. Caudal fin low, fold like. 

 Skin naked, rarely somewhat prickly. Lateral line present, usually with numerous branches 

 anteriorly. Three fiee gills and two half gills. 



KEY TO THE GENERA OF CHIM^ERID^. 



I. Mnlo with cephalic appendage. 



A. Snout soft, not terminating in a cutaneous flap; tail not bent forward. 



1. I'osterior appendages tripartite CniM.KR.\ 



2. Posterior appendages bipartite Hydrolaous 



B. Snout terminating in a cutaneous flap Callouhynchus 



II. Male without cephalic appendage ; snout very elongate Harriotta 



CHIMv^RA, Linnaeus. 



Chimara, LlNNiEUS, Mus. A<1. Frid., i, 53; Syst. Nat., ed. x, 1758, i, 236. 



Holocephali with head somewhat compressed, snout without appendage. Eyes lateral, 

 very large. Lateral line forking anteriorly, forming several series of mucous tubes ou the 

 head. Male with a clnb-.shaped, cartilaginous hook above snout, curved forward and down- 

 ward armed with <lecur\ed spines at tip, and fitting into a depression in front of eyes. 

 V'eutrals rather large, with large bifid or tritid claspers i)i the male. JSIale with also rough 

 a])pendages at the base of the ventrals, protruding from a sheath of skin. First dorsal 

 triangular, preceded by a strong serrated spine which is grooved behind. Secoml dorsal 

 and caudal low, often notched. Tail sometimes produced in a filament. Skin smooth. 



KEY TO THE Sl'IOCIES. 



I. Pectorals long, extending U> tips of ventrals C. moNstrosa 



II. Pectorals short, terminating far in advance of the ventrals C. affinis 



