667 



spines in front of the middle and another at the posterior part; the 2 suc- 

 ceeding segments each with 5 spines, one at the posterior part, a pair in the 

 middle, and another pair of considerably smaller spines at the anterior part; 

 the 3 posterior segments each with a single pair of dorsal spines. Eyes very 

 small, orbicular. Superior antennae rather slender, somewhat exceeding in 

 length half the body, 1st joint of the peduncle the shortest, 3rd joint nearly 

 as long as the 2nd, flagellum much shorter than the peduncle, and composed 

 of about 9 articulations. Inferior antennae very narrow and but sparingly 

 setous, flagellum much shorter than the last peduncular joint. Anterior gna- 

 thopoda of the usual structure. Posterior gnathopoda with the propodos oval 

 in form, palm without any lobe or processes in front, but having posteriorly 

 2 small projections, each tipped with 2 small spines. Branchial lamella"; 

 comparatively small. The 3 pairs of pereiopoda rather slender, propodal joint 

 sublinear, without any distinctly defined palm, but having, beyond the middle, 

 anteriorly, 2 juxtaposed spines of a similar appearance to those defining the 

 palm in other species. Colour light red. Length of adult female 7 mm. 



Eemark. - This form was first described by Leach under the above 

 name. But the name acanfliifcra was subsequently applied by Sp. Bate in 

 his Catalogue of Amphipoda in the British Museum to a very different 

 species, whereas the true Leachian form was described as a new species un- 

 der the name of C. calva. In the subsequent work of Sp. Bate & Westwood 

 this was, however, corrected, and the species C. calva withdrawn as a syno- 

 nym to C. acanthifem. According to Dr. P. Mayer, the 2 species described 

 by Heller as C. hptonyx and C. armata are referable to the same species, 

 and the C. acuminifera of Desmarest and C. liystrix of Kreyer are also be- 

 lieved to be merely synonyms. The species may be easily recognized in both 

 sexes by the peculiar form of the cephalon, which by Sp. Bate is characterised 

 as skull-like. Moreover the structure of the posterior gnathopoda and that 

 of the pereiopoda is rather distinct. 



Occurrence. I have only seen 2 female specimens of this form, which 

 were collected at Korshavn, west coast of Norway, in comparatively shal- 

 low- 'water. 



Distribution. - British Isles (Sp. Bate), coast of France (Chevreux), 

 Azores (Barrois), gulf of Naples (P. Mayer), Adriatic (Heller). - 



