l8o CRUSTACEA MALACOSTRACA. III. 



whole lateral and posterior margin is found a sublinear impression; the margin itself is finely serrate. 

 Exopod of uropods reaches in adduced state slightly beyond the abdomen; it is rather narrow, flat, 

 somewhat curved inwards, and especially on its outer margin finely serrate; its end is bifid, with the 

 inner process several times smaller than the outer. 



Length of the male 4 4-3 mm., of the ovigerous female 47 mm.; Tattersall recorded 5 mm. 

 for both sexes. 



Occurrence. This most interesting form has not been taken by the "Ingolf ', but the "Thor" 

 gathered it at two places. 



South-West of the Faeroes: Lat 6ii5' N., Long. 935' W., 463515 fath.; many spec. 



Lat 6io7' N., Long, g^o' W., 443 fath. ; many spec. 



Distribution. Taken at five places west of Ireland in depths from 199 to 454 fath. (Tattersall). 



Family Anthuridae. 



This family, which occupies a rather isolated position, comprises a somewhat small number of 

 forms. Our knowledge of the family is still somewhat imperfect, as several of the species seem 

 to be rare, and the mouth-parts are very difficult to study. My material from our area is small, com- 

 prising only two species belonging to two genera, while a third species (and genus) had been taken 

 by the "Valorous". The most important paper on the Anthuridse from the North Atlantic is by A. M. 

 Norman and T. R. R. Stebbing: On the Crustacea Isopoda of the 'Lightning', 'Porcupine', and 

 'Valorous' Expeditions. I. (Trans. Zool. Soc. London, Vol. XII, PL IV, 1886). 



In the genera examined here, Cyathura and Calathura, the females have only three pairs of 

 marsupial lamellae belonging to third, fourth and fifth segments; no vestige of such plates could he 

 discovered on second segment. If this number of lamellae is found in all genera, it would afford an 

 interesting character for the family. Thienemann has discovered statocysts in the telson of Anthura 

 gracilis (according to Gurney identical with Cyathura carinata Kr.) and in another species. In Cyathura 

 truncata n. sp. they are easily found in the telson, lying below the dorsal wall at a short distance 

 from its base (PI. XV, fig. 2 q, s); each statocyst contains a single rather large statolith (fig. 2 r), but the 

 duct from the statocyst to the surface was not looked for. In Calathura brachiata a single impaired 

 statocyst is observed near the base of the telson (fig. 33, j); it is a somewhat large, oval, transverse 

 vesicle with a single duct directed upwards, consequently not visible in fig. 3 a; the wall of the vesicle 

 is so well chitinized that it is easy to take it out, but the vesicle of the two specimens examined did 

 not contain any large statolith, but towards its lateral margins at each side several small or extremely 

 small crystals. Whether statocysts are found in other genera is unknown. 



The mouth-parts are extremely difficult to study, and the descriptions and figures in the lite- 

 rature are frequently deficient as to various particulars, so that several statements ought to be applied 

 with caution. 



