1156 
SCANDINAVIAN FISHES. 
lish Channel it has happened" that fishermen who had 
shot long-lines for Cod have found a Rough 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 fish, both crustaceans 
and mollusks, seeming to be especially fond of whelks 
(Buccinum undatum ) and lugworms ( Arenicola ). 
As human food the Rough Hound also finds con- 
sumers among the fishing population and the poor. 
In Scandinavia it is far too 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 Sauvage of Montpellier related in 1745 that a fa- 
mily who had eaten the liver of this fish were over- 
powered by heavy drowsiness, from which they first 
recovered on the third day, and which was attended 
with a skin disease, causing the whole epidermis to 
peel off in fragments. 
CYCLOSPONDYLI. 
Sharks with two dorsal fins, hut no anal. 
Hasse has shown* that the Sharks whose external 
character is expressed in the absence of an anal fin c , 
in their internal characters stand lowest, next the Cow- 
Sharks ( Notidanidce ) — which indeed have an anal fin, 
but only one dorsal — and nearest to the primordial 
forms common to the Sharks and Rays. A comparison 
between our two figures 296 and 297 (see above, pp. 
1068 — 69) shows the great difference in the structure 
of the spinal column between a Cyclospondylous and 
an Asterospondylous Shark. In the former the ver- 
tebra? are far less differentiated. The bodies of the 
vertebrae form a continuous canal, only imperfectly 
coarctated by the constrictions answering to the middle 
parts of fully developed vertebra?. Frequently, though 
irregularly, so-called diplospondylism occurs, two pairs 
of apophyses (two neurals and two inter neurals), or at 
least two pairs of foramina for spinal nerves on each 
side, appearing in a single vertebra. The basal parts 
of the dorsal fins also exhibit a lower grade of diffe- 
rentiation; but in compensation most of the Cyclospon- 
dyli are equipped at the anterior margin of each dorsal 
fin with a spine (ichthyodorulite), which in the species 
our figure (296) represents, however, is considerably 
reduced, not projecting above the skin. 
All the Cyclospondyli have open and rather large 
spiracles. Their eyes are without nictitating membrane. 
All their gill-openings lie in front of the 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 - 
thorhinus ) differs from all the other known Sharks in 
having the duodenum furnished at its commencement 
with a pair of cgecal 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 has divided the Cyclospondyli into three 
families: Lcemargfi, without externally visible dorsal 
“ Brehm, Thierleben , 2:te Aufl., Abth. 3, Bd 2, p. 377. 
b Naturl. Syst. Elasmobr., Allgem. Th. p. 41; Besond. Th., p. 55. 
c Squales anhypopteriens Moreau, Hist. Nat. Poiss. Fr., tom. I, pp. 276 and 340. 
d This observation may be traced even in Gunnerus (Trondhj. Selsk. Skr., vol. II, pi. X, fig. 2), but is unnoticed in the text. 
e See Lutken, Vid. Meddel. Naturh. For. Kbhvn 1879 — 80, p. 56. A female Greenland Shark 23 dm. long was taken in the North 
Sea during January, 1891, and presented by 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 within them of the impregnated eggs. 
f Containing the genera Acanthorhinus , Isistius , Euprotomicrus , and Scymnus. 
