1898-1902. No. 18.] CRUSTACEA. 31 



carrying at some distance from the tip a strong deflexed spiniform 

 appendage accompanied by another much thinner appendage. Last pair 

 of legs very small, distal joint quite short, with only 5 setae, 2 of them 

 attached to the inner edge ; inner expansion of proximal joint tipped 

 with 2 unequal setae. 



Length of adult female 0.77 mm. 



Remarks. The present form is easily distinguishable from 



the preceding species and also different from any other species known 

 to me. In the shape of the rostrum and the 1st pair of legs it some- 

 what resembles A. imus (BRADY); but the body is far less slender, and 

 the structure of the last pair of legs is also very different. 



Occurrence. Several specimens of this form occurred in a 

 bottle of specimens taken on July 12, 1900, in the bay at Land's End. 



109. Amphiascus brevis, G. 0. SARS, n. sp. 

 (PI. VIII, figs. 11-15). 



Specific Characters. Female. Body unusually short and 



stout, with the anterior division slightly dilated in the middle and some- 

 what narrowed both in front and behind. Rostrum of moderate size 

 and obtusely pointed at the tip. Urosome considerably shorter than 

 the anterior division, with the last segment about the length of the pre- 

 ceding one. Caudal rami broader than they are long, inner medial 

 seta conspicuously dilated at the base and not quite twice as long as 

 the urosome. Anterior antennas rather slender, 8-articulate, with the 

 4th joint longer than the 3rd, terminal part about half the length of the 

 proximal one. 1st pair of legs with the outer ramus exceeding half 

 the length of the inner, and having the last joint about as long as the 

 middle one, its armature as in the 2 preceding species; inner ramus 

 with the 1st joint long and slender, seta of inner edge comparatively 

 short, outer 2 joints less unequal than in A. polaris, the last one being 

 only slightly longer than the other, and armed at the tip with a mode- 

 rately slender, almost straight claw and a long seta accompanied by a 

 small bristle. Natatory legs normal. Last pair of legs comparatively 

 smaller than in the preceding species, distal joint narrow oval in form 

 and somewhat exserted at the end, marginal setae 7 in number, 2 of 

 them being attached to the inner edge; inner expansion of proximal 

 joint extending to about the middle of the distal joint and carrying 

 5 setae. Ovisacs about as in A. polaris. 



Length of adult female 0.52 mm. 



