COMMON SEA-CAT. 
233 
of growth undergone by these parts of the body, run 
in opposite directions. Round the eye there is a ring 
of tine, white pores or dermal openings of the system 
of the lateral line. Similar pores also occur, in the 
usual manner, along the lower jaw and on the sides 
of the head, which are covered with a thick skin, en- 
tirely enveloping the bones of the gill-cover. The 
nostrils are set about half-way between the snout and 
the eye, one on each side, and are raised into cy- 
lindrical dermal tubes. The mouth is middle-sized and 
furnished with fleshy lips, which form thick folds, 
especially at the corners. In consequence of the firm, 
cartilaginous connexion between the strong, but short, 
intermaxillary bones and the front part of the skull 
(the point of the ethmoid bone), the upper jaAV admits 
of only slight motion, and the opening and closing of 
the mouth are performed almost entirely by the lower 
jaw. On each side of the intermaxillary bones we find 
two or three strong, conical teeth, widened and grooved 
at the base, like the tusks of the predatory mammals, 
but blunt at the top, set one in front of another, and 
each fastened to a hard osseous socket. Within these 
teeth is a row of 5 or 6 (in old specimens generally 
fewer) smaller, somewhat compressed, shorter teeth. 
On the palate are three double rows of thick, globular 
teeth, with raised, osseous bases. In the middle row, 
which contains the largest teeth, and is set on the 
vomer, there are generally four pairs of teeth with an 
even, worn surface, the penultimate pair being con- 
siderably larger than the others. In each of the lateral 
palatine rows there are two rows, each containing four 
or five blunt teeth, those of the one row alternating 
with the other; and these rows are attached to the 
two palatine bones. In the front of the lower jaw there 
are from 4 to 6 tusk-like teeth in a row, and within 
this row begin the two longitudinal rows of shorter, 
globular jaw-teeth, molars with flat, worn crown and sur- 
face sloping inwards. Of these molars the middle ones 
are the largest. In the roof of the throat there are 
three upper pharyngeals on each side, united together 
into a roundish bone, and furnished with scattered, 
cardiform, conical and curved teeth; and beneath these 
two longer lower pharyngeal bones with similar teeth, 
forming an angle in front. The tongue is fleshy, but 
short, somewhat pointed and toothless. The four branch- 
ial arches are furnished in front with spines covered 
with skin. The gill-openings are of moderate size and 
almost vertical. The branchiostegal membranes are 
furnished with 7 rays and inferiorly united to the isth- 
mus, just below the insertion of the pectoral fins. 
The body is covered with a thick and tough skin, 
which at first sight seems to be scaleless and protected 
only by an abundant, mucous secretion; but on closer 
examination we find small, round, thin scales, deeply 
imbedded in the skin and scattered, not contiguous. 
The lateral line is hardly visible, being most distinct 
in the anterior part of the body, where the dermal 
pores which belong to it, are generally clearly marked 
by their white colour. The line runs almost straight 
along the middle of the body. The vent is large, some- 
what pendent and situated a little in front of the 
middle of the body. 
The dorsal fin begins somewhat in front of the 
perpendicular from the insertion of the pectoral fins, 
the distance between it and the tip of the snout being 
always somewhat less than the length of the head, and 
runs with fairly uniform height along the back very 
close to the caudal fin, where it ends in an obliquely 
truncate and rounded corner. All the rays are simple 
and unarticulated, but only the last 10 — 13 are really 
hard, all the others being soft and flexible at the tip. 
The whole fin is united by a thick and slimy mem- 
brane. The anal fin is of the same shape as the dorsal 
fin, but scarcely half as high, and ends in a pointed 
corner vertically below the end of the latter. The first 
ray is unarticulated, but soft; all the other rays are 
articulated, the anterior ones being simple, the posterior 
branched at the tip. The pectoral fins are large and 
rounded; when expanded, they are almost circular. 
Their branched, thick, weak and fleshy rays give them 
a striate appearance, which reminds us of the shell of 
the scallop ( Pecten ). Their length in proportion to that 
of the body diminishes with age, varying from about 
16 to slightly more than 13 % thereof. The ventral 
fins are wanting. The caudal fin is small, with rounded 
tip and 20 or 21 rays, only 13, however, being branched, 
and only the 11 middle ones extending to the true 
hind margin of the fin. 
We have not remarked any considerable difference 
between the sexes. 
The colour is a uniform dark gray. The sides 
are marked with more or less distinct, black transverse 
belts, which vary in number and shape, and are gener- 
ally composed of a number of confluent, small spots. 
The belts are continued, though more indistinctly, on 
the dorsal fin. The colour of the eye is very dark, 
Scandinavian Fishes. 
30 
