I9 8 CRUSTACEA MALACOSTRACA. III. 



139. Astacilla longicornis Sowerby. 

 1806. Oniscus longicornis Sowerby, Brit. Miscellany, T. 19. 

 ! 1897. Astacilla G. O. Sars., Account, II, p. 88; PL 36. 



The largest specimen, a female with marsupium, is 24^5 mm., while the male is only 12 mm. long. 



Occurrence. Not taken by the "Ingolf". But it has been gathered by Cand. mag. Ad. Jen- 

 sen (in the "Michael Sars") south of the Faeroes at Lat. 6o°55' N., Long. 8°56' W., 69 fath., temp. 9"33°; 

 many spec. — In Sars' work we find Iceland in his list on the distribution of this species; he said the 

 same in the Norw. North-Atl. Exp. Crust. II, p. 31, and Tattersall (1905) has also Iceland, perhaps on 

 the authority of Sars. But Sars himself had not gathered the species at Iceland, and I have been 

 unable to find in the literature any first-hand record on the topic. Our Museum has no specimens 

 from Iceland, and it is not very probable that this large species lives there without having been dis- 

 covered by any of the Danish zoologists, who have collected Crustacea at a large number of places 

 along the coasts or in the Fjords. Until it has been captured I think it better to suppose that some 

 error has caused Iceland to have been noted by Sars and Tattersall. 



Distribution. A. longicornis has been taken in about the northern half of the Sound and 

 vStore Belt, and in Kattegat and Skager Rak, in from 5 to about 50 fath. (H. J. Hansen). At Norway it 

 "would seem to occur along the whole coast", even to Vadso, generally in 10 to 30 fath. (G. O. Sars). 

 According to A. M. Norman it is known from Shetland and all the coasts of Great Britain and Ireland, 

 while Zirwas recorded it from some places in the North Sea, 18 — 180 fath.; west of Ireland it goes 

 down to such considerable depths as 199 and 360 fath. (Tattersall). It is recorded from Guernsey 

 (Norman), but as to its distribution further south nothing seems to be known. 



140. Astacilla (?) arietina G. O. Sars. 

 (PI. XV, figs. 8 a-8 b). 

 1883. Astacilla arietina G. O. Sars, Forh. Vid. Selsk. Christiania for 1882, No. 18, p. 62; PI. 2, fig. 2. 

 1897. ~~ G. O. Sars, Account, II, p. 90; PI. 37, fig. 1. 



The single specimen is a young female, 11 mm. long. It differs from the figures of Sars in 

 the three following particulars. The fourth thoracic segment possesses the two pairs of knots on the 

 anterior dorsal half, but both are distinctly smaller than in Sars' figures, and between them are two 

 pairs of considerably smaller knots; furthermore the dorsal surface behind the second pair mentioned 

 have a number of knots more elevated than figured by Sars. The uropods (fig. 8 a) are conspicuously 

 shorter in proportion to abdomen than figured by Sars, as the distance from their end to the tip of 

 abdomen is nearly half as long as the uropods. Finally the relative length of the joints in the anten- 

 nal flagellum differs much from Sars' figure, the first joint being only about as long as the sum of 

 the two distal joints (fig. 8 b), while according to Sars the first joint is twice as long as that sum. 



The result is that it is a little doubtful whether my specimen belongs to A. arietina or to a 

 hitherto unknown species. But as the specimen possesses the projecting pair of protuberances on the 

 head and two pairs of the dorsal tubercles on fourth segment larger than the others, I think the deter- 

 mination might be correct, especially as the specimen is far from adult, and my material of specimens 



