others, and densely plumose. Anterior antennae much shorter than the cephalic 

 segment, and composed of 20 articulations, terminal part very short, though 

 having all 3 joints well defined. Posterior antennas with the penultimate joint 

 somewhat shorter than the preceding one; terminal joint distinctly subdivided in 

 the middle. Oral cone scarcely extending beyond the insertions of the anterior 

 maxillipeds, and having the outer part abruptly narrowed. Mandibles with the 

 masticatory part narrow styliform. Maxillae with the inner lobe short and 

 thick, transversely truncated at the end; principal seta very largely developed, 

 extending far beyond the insertions of the maxillipeds, and densely plumose; 

 outer lobe much smaller, and having the apical setae comparatively short. Max- 

 illipeds rather powerfull; claw of the anterior ones very strong and curved at 

 the end in a hook-like manner. Natatory legs largely developed, with the middle 

 joint of the inner ramus in 1st pair unusually broad and expanded. Last pair 

 of legs with the distal joint oval in form and rounded at the extremity, which 

 carries 2 seta3 accompanied by a small bristle. Ovisacs comparatively small, 

 oval in form. 



Colour somewhat variable, in some cases dark violaceous, in other cases 

 much paler. 



Length of adult female 0.90 1.10 mm. 



Remarks. This form, as above mentioned, was first described by Glaus 

 as the type of his genus Echinocheres. Another species of smaller size was also 

 recorded by the same author under the name of Echinocheres minutus, and this 

 species has likewise been observed by Giesbrecht, who admits its specific difference. 

 The very close relationship between these 2 species, both as to structural 

 details and habits, would indeed seem to justify the opinion of Glaus, that they 

 should be kept apart under a separate genus. The Ascomyzon Thompson* of 

 A. Scott is unquestionably identical with the present species. 



Occurrence. I have taken this form occasionally from 3 different Echi- 

 nids, viz., Strongylocentrotus drobachiensis (small variety), Echinus sphcera and 

 Echinus elegans, all collected off the west coast of Norway from different depths. 

 The specimens found on the first-named Echinid were all of a very dark viola- 

 ceous colour, like that indicated in the coloured figure given in Giesbrecht's 

 work on PI. 1; whereas those occurring on the other 2 Echinids were much 

 paler, of a whitish grey hue, with a very slight rosy tinge. These specimens 

 were also of a somewhat larger size, but otherwise fully agreeing with the dark- 

 coloured variety. Giesbrecht also mentiones the variability of colour in the pre- 

 sent species. 



Distribution. British Isles (Scott), Triest (Glaus), Gulf of Naples (Giesbrecht). 



