874 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



Monstrosities. — Abnormalities of a marked kind were not frequent in the marine 

 larval fishes hatched in the laboratory. Amongst these observed, however, were a 

 double-headed example of Pleuronectes limanda (PL V. figs. 3 and 3a, in ovo), the 

 latter figure being taken three days later than the former, and when the pigment had 

 appeared. A cyclopean embryo of Trigla gurnardus, again, is represented in the same 

 Plate, fig. 5, other abnormalities being present in the ovum. An abnormal tail of the 

 same species, referred to elsewhere in this paper, is also shown on PI. XIV. fig. 3. The 

 notochord with its investment continues in the axis of the body, while the caudal region 

 bends separately to the left. 



XIII. Anarrhichas lupus, L. The "Wolf-Fish. Development and Life-History, 

 with Remarks on the Salmon and other Forms. 



Intra-Ovarian Ova. — The intra-ovarian ova of the wolf-fish had been met with occa- 

 sionally during the work for H.M. Trawling Commission, it being stated in the Report 

 that they were of considerable size in February, and that at this period an abnormal ex- 

 ample of a large ovum (which had not been discharged) was observed. In August, again, 

 the ova were more than an eighth of an inch in diameter — in fact, it was clear that the 

 spawning period of this fish was late, and in contradistinction to the published views on 

 the subject. Thus, Day* mentions that, " according to Pennant, it spawns in May and 

 June, when it deposits its ova on the leaves of marine plants ; the fry are of a greenish 

 colour." Parnell, also quoted by this author, states that " about June the young are 2 

 feet in length." t That it could not spawn in May or June was evident by an examina- 

 tion of a specimen 3 feet 1 inch long. The ovaries were 6 inches long and about 1\ inch 

 in transverse diameter as they lay on a flat surface, connate from the posterior end forward 

 nearly a third of their length, and fixed by strong membrane in front of the fork. The 

 ova form dense masses along the inner edge of each ovary, the great bulk of the eggs 

 occurring there, for those on the rest of the surface were less numerous. The majority of 

 the eggs are nearly of equal size, viz., about 1*5 mm., and each is invested by a vascular 

 follicular membrane with very fine epithelium. Amongst these, however, many minute 

 ova (visible to the naked eye) occur, and ranging from '75 mm. downward. In these the 

 capsule is thick, the contents coarsely granular, and the nucleus large. A single large 

 egg, about 6 mm. in diameter, and with an oil-globule 175 mm., was present, having 

 evidently been retained after the others had been shed, as occasionally happens to other 

 fishes — both marine and fresh water. The arrangement of the ova along the inner (i.e., 

 median) border of each ovary was lamellar, masses of eggs hanging from the wall, so that 

 it was on the whole roughly fimbriated. Minute blood-vessels covered each egg and 

 the intervening membrane. In the very early stage the ovum lies in a capsule in the 

 epithelial membrane of the ovary, and shows a large nucleus and nucleolus ; while the 



* Op. cit., p. 196. t Fishes of the Firth of Forth, p. 240. 



