tumefied, last small, claw-like and very mobile. Last pair of legs with the distal 

 joint of exactly the same appearance as in the female, proximal one, however, 

 much smaller and not at all expanded. 



Colour pale yellow, sometimes with a faint rosy tinge. 



Length of adult female 0.56 mm., of male 0.44 mm. 



Remarks. This form was briefly described by G-oodsir as early as the 

 year 1845, and has subsequently been observed by several other authors. The 

 Arctic form, Z. Aurelii of Poppe, is jery nearly related to this species, scarcely 

 differing except in the form of the distal joint of the last pair of legs, which is 

 comparatively narrower and more produced at the tip. 



Occurrence. I have met with this form not unfrequently along the greater 

 part of the Norwegian coast, and I am disposed to believe that the form recorded 

 by Th. Scott from Finmark as Z. Aurelii Poppe, may more properly be referable 

 to the present species. It is a strictly littoral form, living near the shore among 

 algae, and is occasionally left in tidal pools together with other littoral species. 

 The flattened form of its body makes it very easy for it to run along the fronds 

 of the algae or other smooth objects. Male and female are often found tied to- 

 gether in copula, as figured by Glaus. 



Distribution. British Isles (Goodsir), Heligoland (Glaus), coast of France 

 (Canu), Arctic Ocean, at Novaja Zemlia and Franz Josefs Land (Scott). 



36. Zaus abbreviate, G. 0. Sars, n. sp. 



(PI. XXXII). 



Specific Characters. Female. Body very flat, shield-like, rounded oval 

 in outline, with the segments of the anterior division lamellarly expanded later- 

 ally. Cephalic segment broadly rounded in front, rostrum broad, lamellar, obtusely 

 truncated at the tip. Last pedigerous segment very small. Urosome comparatively 

 short and broad, not nearly attaining half the length of the anterior division; 

 genital segment considerably expanded and densely ciliated at the edges, postero- 

 lateral corners of this and the succeeding segment conically produced. Caudal 

 rami about as in Z. spinatus. Anterior antennae with the terminal part very short, 

 scarcely longer than the preceding joint. Posterior antennae and oral parts re- 

 sembling in structure those parts in the preceding species. First pair of legs like- 

 wise rather similar, though with the distal joint of the outer ramus comparatively 

 longer and less --dilated towards the end; inner ramus armed at the tip with 2 

 spines, one of which is digitiform and quite smooth. Natatory legs comparatively 



