109 



Remarks. This form has been erroneously identified by Prof. Brady with 

 T. rufoviolacens of Glaus, from which it differs conspicuously both as regards the 

 general form of the body and some of the anatomical details. The figure of the 

 animal given by Brady is somewhat misshapen, apparently owing to a strong 

 pressure of the mounted specimen from which the drawing was made. 



Occurrence. Some few female specimens of this form were found, many 

 years ago, off the west coast of Norway, at Molde and Christiansund. 



Distribution. British Isles (Brady). 



69. Thalestris purpurea, G. 0. Sars, n. sp. 



(PI. LXIV). 



Specific Characters. Female. General form of body very similar to that 

 in T. brunnea, being conspicuously depressed throughout. Cephalic segment, how- 

 ever, seen dorsally, more .regularly rounded in front, and having the lateral cor- 

 ners more produced. Rostral projection abruptly recurved, with the tip bluntly 

 rounded. Penultimate segment of urosome forming a thin expansion behind, arch- 

 ing over the last segment and divided into 4 regularly rounded lobules. Caudal 

 rami of much the same structure as in T. brunnea. Eye still larger than in that 

 species, and on each side applied to a distinct lenticular thickening of the integu- 

 ment. Antennae, mandibles, maxillss and anterior maxillipeds almost exactly as 

 in T. brunnea. Posterior maxillipeds, however, comparatively less powerfully 

 developed, hand less curved outside, and not having the palm at all defined in 

 front. First pair of legs resembling in structure those in T. brunnea, though 

 having the apical claws of both rami somewhat more elongated. Last pair of 

 legs likewise very similar, distal joint, however, more oblong in form, and the 

 marginal spines of proximal joint less elongated. 



Colour of body a deep crimson, dorsal face of cephalic segment some- 

 what lighter. 



Length of adult female 0.96 mm. 



Remarks. This form is very closely allied to T. brunnea, and indeed 

 preserved specimens of the two may be easily confounded. In the living state, 

 however, the present form is at once recognized by the deep crimson colour of its 

 body. On a closer comparison, some well-marked differences in the anatomical 

 details are also found to exist, proving these 2 forms to be in reality specifically 

 distinct. The shape of the rostrum is rather different, for instance, and the pos- 

 terior maxillipeds are somewhat dissimilar in size. The regularly 4-lobatc lamellar 



15 Crustacea. 



