ii')(; 



SCANDINAVIAN FISHES. 



lish Channel it has hap|)ened" that Mshermen who had 

 sliot long-lines for Cod have f(juiid a Kouuh Hound on 

 almost every hook; and the hooked Cod had been de- 

 voured down to the head and a bit of the backbone. 

 The Rough Hound eats, besides tish, both crustaceans 

 and inollusks, seeming to be especiall)' fond of whelks 

 {Buccinum undatum) and lygworms (Arenicola). 



As human food the Rough Hound also finds con- 

 sumers among the fishing population and the poor. 

 In Scandinavia it is far tc^o rare to possess any eco- 

 nomical importance. Not so in France and the rest 



of Southern Europe. Its skin is used in polishing 

 various substances. Its hard flesh and musky odour 

 are disagreeable, but the latter is said to be removed 

 by boiling. The liver, which is described as having 

 an abominable taste, is considered poisonous. One Doc- 

 tor Salvage of Montpellier related in 174.5 that a fa- 

 mily who had eaten the liver of this fish were over- 

 powered b)' heavy dro^vsiness, from which they first 

 recovered on the third day, and which was attended 

 witli a skin disease, causing the whole e])idermis to 

 peel oft ill fragments. 



CYCLOSPONDYLI. 



Sharks with tiro dorsal fius, but no anal. 



Hasse has shown' that the Sharks whose external 

 cliaracter is expressed in the absence of an anal fin'', 

 in their internal characters stand lowest, next the Cow- 

 Sharks {Notidanida) — which indeed have an anal fin, 

 but onl}' one dorsal — and nearest to the jjiimordial 

 fopms common to the Sharks and Rays. A comparison 

 between our two figures 296 and 297 (see above, pp. 

 1068 — 69) shows the gi*eat difference in the structure 

 of the spinal column between a Cyclospondylous and 

 an Asterospondylous Shark. In the former the ver- 

 tebrae are far less differentiated. Tlie bodies of the 

 vertebra form a continuous canal, onl}- imperfectly 

 coarctated by the constrictions answering to the middle 

 parts of full)' developed vertebra-. Frequently, though 

 irregularly, so-called diplospondylism occurs, two pairs 

 of apophyses (two neurals and two interneurals), or at 

 least two pairs of foramina for spinal nerves on each 

 side, appearing in a single vertebra. The basal parts 

 of tlie dorsal fins also exhibit a lower grade of ditt'e- 



rentiation: but in conqjensation most of tlie Ci/clospoH- 

 djjli are equipped at the anterior margin of each dorsal 

 fin with a spine (ichthj'odorulite), which in the species 

 our figure (296) represents, however, is considerably 

 reduced, not projecting above the skin. 



All the Cijclospondi/li have open and rather large 

 spiracles. Their eyes are without nictitating membrane. 

 All their gill-openings lie in front of tiie pectoral fins. 

 Their caudal fin is generally less heterocercal than that 

 of other Sharks. Most of them are characterized by 

 the singular form of the jaw-teeth. One genus {Acan- 

 fhorhinus) differs from all the other known Sharks in 

 having the duodenum furnished at its commencement 

 with a pair of Cctcal appendages''. The great majority of 

 them are known to be viviparous; but one species of the ge- 

 nus just mentioned, the Greenland Shark, has been sus- 

 pected in recent times to form an exception to this rule'. 



Hasse lias divided the Ci/clospondi/U into three 

 families: Lfemarr/i', without externally visible dorsal 



° Brehm, Thierleben, 2:te Aufl., AbUi. 3, Bd 2, p. 377. 



' Nattirl. S;/st. Elasmobr., Allgeni. Th. p. 41; Besond. Th., p. 5.5. 



'^ Squales anhypopteriens Mokeau, Hifl. Nat. Poiss. Fr., torn. I, pp. 276 and 340. 



"* This observation may be traced even in Gunnebus (Trondhj. Selsk. Skr., vol. II, pi. X, tig. 2), luit is unnoticed in llie text. 



' Sec LDtken, Vid. Meddel. Naturh. For. Kbhvn 1879 — 80, p. 56. A female Greenland Shark 23 dm. long was taken in the North 

 Saa during January, 1891, and presented bj' Mr. Fredericksen of Copenhagen to the Royal Museum. The oviducts lay, as Turner (Journ. 

 Anat., Physiol., vol. XII [1877 — 78], p. 604) also found them, extended from the diaphragm to the cloaca, straight and thin-walled, gra- 

 dually expanding in the hindmost part alone to the thickness of a goose-quill, and here with somewhat stouter walls than in front, but with- 

 out any special dilatation whatever throughout their extent. From this circumstance it is, however, impossible to decide with certainty the 

 appearance presented by the oviducts after the act of copulation and the development witliin them of the impregnated eggs. 



.'' Containing the genera Acantlwrhinus, histius, Euprotomicrus, and Scyimius. 



