On the Eggs of certain Skates {Rata). "5 



Rata fullonica, L. (Shagreen Ray). — The purse of this fish resembles 

 that of circularis, but it is of larger dimensions (fig. 3). 



Raia lintea, Fr. — Two purses were obtained by Mr. Erlendsson in a 

 female taken in 70-80 fms., 16 miles S.W. of Snaefellojoteul, Iceland, 

 in June. The purse resembles that of Raia fullonica (fig. 3), but it 

 is larger. One example had a body 11 cm. long by 8 cm. wide. The 

 longer horns were 10 to 11 cm. in length. The little horns were 

 shorter than the little horns in Raia fullonica. 



Raia radiata, Donovan. — This purse is the smallest of those 

 described in this paper. The test is felty on the outside. Some 

 silky hairs hung loosely from the purse. Beard says that it is always 

 quite flat on one side and strongly convex on the other. The embryo 

 is usually found under the flattened side of the purse. He further 

 states that the purses of this species were plentiful at Aberdeen in 

 February and March, and continued to be got until June at least. I 

 received from Mr. Eunson two purses taken from the skate in 

 October. 



Raia oxyrhynchus, L. — This purse (fig. 9) was found in the cloaca 

 of the fish. It has a felty external surface. It contained no ovum. 

 The sides of the end of the purse marked x. in the figure were adhering 

 together, but they were readily separated. The remains of j^ellow 

 yolk were found inside the purse. The egg had been expelled b}^ 

 violence before the mouth of the purse had been properly sealed. 

 Along the lateral edge of the purse there was a border of woolly stuff 

 which resembled the material of which the tendrils of batis Avere 

 composed, but here it was attached along the whole edge. 



Raia alba, Lacep : Raia marginata, Lacep. — The Bottle-nose Ray. 

 A purse taken from the bottle-nose ray is described by Holt.* It 

 does not appear to difier greatly, in so far as concerns the shape of 

 its body, from that of R. batis. Its greatest length in the middle line 

 was 6-^ inches (17"4 cm.), and its greatest breadth was 5y^ inches 

 (13'8 cm.). The posterior horns, about 3y^^ inches (87 cm.) in length, 

 are stout, flattened, and tapering. They are strongly bent in a 

 ventral direction, and incline semewhat towards each other. The 

 anterior horns are long and ribbon- like. They are 9f inches 

 (24-5 cm.) in length, and they taper from a width of -| inch (2-2 cm.) 

 to one of about ^ inch ("6 cm.) at the extremity. They are ver}^ 

 thin, and are supported by a thickened longitudinal ridge. Each 

 horn is inwardly curved so as to meet and cross its fellow. The axis 

 of the ribbon is gradually rotated. The fine longitudinal ridges on 

 the surface of the purse are most distinctly beaded. Each is, in fact, 

 beset by minute transverse crests. This beaded appearance seems to 

 be quite characteristic. Coiich f and Day $ describe a purse which 

 they believed to belong to Myliohatis aqiiila. It is the purse of the 

 Bottle-nose Ra3^ 



According to Bugnion,§ the average weight of the egg of R. alba 

 is 90 grammes. 



* Holt, E. W. L. — "The Bottle-nose Ray (? Raia alba, Lacep), and its Egg- 

 purse." Journal of the Marine Biological Association. Vol. V. (N.S.). 1897-99. 

 Pp. 181-183. 



t Fishes of Great Britain. 



I British Fishes, i. 



§ Bugnion, E. — Le Developpement des Selaciens (Acanthias vulgaris, et 

 Scyllium canicula) et des Raies {Raia alha, R. clavata). Proces-Verbaux. 

 Pp. xxxi-xxxiv. Bulletin de la Societe Vaudoise des Sciences Naturelles. 3e S. 

 Vol. XXX. No. 115. Lausanne, 1894. 



