115 



best recognized by the absolute want of lateral spines, and the pale colour of 

 the body. 



Occurrence. — Though nowhere in any abundance, I have met with this 

 form in several places on the west coast of Norway, and always in rather con- 

 siderable depths, ranging from 60 to 150 fathoms. 



Distribution. — British Isles (Robertson), Kattegat (Meinert). 



3. Pleurogonium spinosissimum, G. 0. Sars. 



(PL XLVIII, fig. 2.) 



Pleuracantha spinosissima, G. 0. Sars, Beretning om en i Sommeren 1865 fovetagen zool. Eeise 

 ved Kysterne af Chxistiauias og Christiansands Stifter, p. 30. 



Specific Characters. — Body oblong oval in form, slightly tapering posteriorly. 

 Cephalon blunted in front, and slightly emarginated on each side at the insertion 

 of the superior antennas. Lateral parts of the 4 anterior segments of mesosome 

 irregularly angular, and each projecting into 2 diverging serrated processes, the 

 anterior of which more properly represents the produced coxal plate of the cor- 

 responding segment. The 3 posterior segments of mesosome, as usual, much 

 smaller than the anterior, and • each having laterally a single strong, serrated 

 spine, likewise representing the produced coxal plate. •Caudal segment rather 

 large, obcordate, lateral edges considerably bulging in the middle and densely 

 hairy in their outer part, tip acutely produced. The' several appendages of the 

 body resembling in structure those in the 2 preceding species, excepting that the 

 female operculum is comparatively much broader and very acutely produced at 

 the tip. Colour bright red. Length of adult female 3 mm. 



Remarks. — This is a very distinct species, easily recognizable from the 

 other known forms by the coarse armature of the body, which, indeed, has given 

 rise to the specific name. It is also of considerably larger size. 



Occurrence. — I have found this pretty species occasionally in several lo- 

 calities of the Norwegian coast, from the Christiania Fjord to Vardo, in depths 

 ranging from 50 to 100 fathoms. 



Distribution. — British Isles (Eobertson), Kattegat (Meinert). 



