218 ACANTHOPTERYGII. 



Length of head 9|, of caudal fin 9|, height of body 6 in the total length. 

 Eye — lateral, diameter 3 in the length of the head, 1 diameter from the end of the 

 snout, and 1/2 a diameter apart. (In an example captured at the Orkneys in 1817 

 the height of the body was 6| in the entire length.) Body very strongly 

 compressed : its height continuing much the same to within the last fourth of the 

 length of the body, when it suddenly decreases and becomes very low at the 

 caudal peduncle. Teeth — small (in the maxilla nearly recumbent, thin and 

 pointed, with the apices pointing towards the phar3'nx : two on either side of the 

 upper jaw : three or four on each side of the lower : one or two teeth on the 

 Tomer, but none on the palatines in T. arcticus). Fins — the dorsal commences 

 above the posterior end of the opercle, its rays are simple and not articulated : 

 its first few are low (no anterior elongated portion as described in T. arcticus 

 exists). The fin gradually becomes higher, attaining its greatest elevation in the 

 posterior fourth of the length of the back, but gradually diminishes in height as 

 it approaches the caudal fin, on to which it is not continued. Pectorals very short, 

 situated low down and close to the head, and with five rays (10-11 in T. arcticus). 

 No ventrals (said to exist in T. arcticus and to consist of six rays, Dr. Dnguid 

 also observed minute ones in some Orkney examples). Caudal with seven minute 

 rays at Montrose, eight in that at Norwich, it is situated slightly above the 

 longitudinal axis of the body : close to its base and on the inferior edge of the 

 caudal peduncle exists a short spine pointing forwards, and three or four smaller 

 ones behind it (some have supposed this to be a rudimentary anal fin). Vent 

 situated midway between the hind edge of the eye and the base of the caudal 

 fin. Lateral-line — almost straight, and slightly nearer to the abdominal than it is 

 to the dorsal profile : it consists of a row of oval bony plates having a central 

 spinate prolongation to each, and which increase in size towards the tail. Some 

 hard warts exist along the edge of the abdomen. Colours — silvery, with 

 indications of light longitudinal lines, but no black spots (as stated to exist in 

 T. arcticus) . Fins red, the caudal tinged with darker. 



The foregoing descriptions are taken from the three specimens I have personally 

 seen at Norwich, Newcastle, and Montrose. Whether the first of these had or had 

 not a ventral fin appears doubtful. Mr. Southwell observes that " Mr. Rump, 

 who first saw it, says it had two singularly rounded fins at the V." (ventral) ; but 

 when he examined it " the ventral fins mentioned by Mr. Rump had disappeared." 

 Reinhardt found them in both examples of T. arcticus from Iceland which he 

 examined. I could not see any indications of them. There was no anterior dorsal 

 fin consisting of elongated rays, while "Mr. Cole tells me that it was a male" 

 (Southwell). These British forms would appear to be identical with Professor 

 Lilljeborg's specimens sent from Tromso to Nilsson who considered it might be 

 distinct from T. arcticus ; but Dr. Dnguid, ^having observed minute ventrals 

 in some Orkney examples, renders it possible that all may belong to one species. 



In a paper upon the different species of this genus, and especially on the 

 metamorphoses of T. tcenia, C. Emery* comes to the conclusion that T.filicauda, 

 Costa ; T. spinolce, Cuv. and Val. ; T. tcenia, Bloch ; and T. iris, Walb., are names 

 given to the successive stages of one and the same species, viz., T. tmnia. He 

 gives particulars of twenty-three specimens which he had examined. 



Professor Gill, with great probability, suggests that Hoy's fish, found Nov. 

 2nd, 1810, and described as Tricliiurus lepturus (Trans. Linn. Soc. xi, p. 210) was 

 apparently a Trachypterus, the height of the body equalling about six in the total 

 length ; its greatest thickness being only one inch, &c. 



Names. — Deal-fish, due to its thin form. Vaagmaer, from its Icelandic name. 



Habits. — Olafsen says (Voy. Iceland, p. 692) that it is rare even in Iceland : 

 it seems to approach the shore at the flood tide in places where the bottom is 

 sandy and the shore not steep, and here it remains until left dry. Nilsson remarks 

 that it is termed Siilv queite or " Silver holibut," its name signifying its colour, 



* Atti Ace. Rom. (3) Mem. Sci. Fis, iii, pp. 390-395, fig. 1-6, and Mt -i. Stat. Neap. 1879, i, 

 p. 581. 



