- i3 - 



between the two cases are so conspicuous that no mention 

 is needed. And having attempted to put all necessary 

 details before the reader I will abstain from any discus- 

 sion or speculation. 



It may be added that in Thysanoëssa spinifera the eyes 

 are a little higher than broad, a little narrowing upwards 

 but without any perceptible constriction ; first pair of legs 

 vary rather inconsiderably, being scarcely or a little longer 

 and slightly or conspicuously stronger than second pair ; 

 seventh joint is a good deal shorter and somewhat thicker 

 in first than in second pair, and the setas along the lower 

 margin of sixth joint are nearly or quite naked in first pair, 

 distinctly plumose in second pair. But I have not found 

 any specimen with the first pair of legs developed either 

 as in the « form » Rhoda inermis or as in specimens of 

 T. inermis with the same pair strongly thickened. Of the 

 species hitherto named Rhoda Raschii M. Sars I have not 

 seen any specimen with the first pair of legs developed as 

 in a typical Thysanoëssa ; in all other species of Thysa- 

 noëssa not already mentioned in this chapter I have always 

 found the first pair of legs conspicuously longer and at 

 least somewhat stronger than second pair, but at least in 

 several species the first pair of legs vary somewhat or 

 even much as to length and thickness in specimens of the 

 same species. 



(210) 



