178 



length of the anterior division. Caudal rami very small, somewhat narrowed 

 distally, apical setae normal. Eye small, but distinct. Anterior antennae rather 

 slender and attenuated, 8-articulate, 2nd joint the largest, 4th joint scarcely twice 

 as long as 3rd, terminal part about half the length of the proximal one. Posterior 

 antennae with the outer ramus very small, being much shorter than the last joint 

 of the inner, middle joint without any seta. 1st pair of legs with the outer ramus 

 about as long as the 1st joint of the inner, middle joint without any seta inside, 

 last joint considerably longer, and armed with 2 spines and 2 geniculated setae; 

 inner ramus with the last joint more than twice as long as the preceding one, 

 both together somewhat exceeding half the length of the 1st. Natatory legs with 

 the rami almost equal-sized, number of setae much reduced. Last pair of legs 

 with the distal joint oblong, narrowly exserted at the tip, and carrying 5 some- 

 what unequal marginal setae, that issuing from the tip being the longest; inner 

 expansion of proximal joint narrow linguiform, and extending somewhat beyond the 

 middle of the distal joint, marginal setae 5 in number, the 2 innermost compara- 

 tively short and spiniform. Ovisacs rather narrow and only slightly divergent. 



Male with the 2nd basal joint of 1st pair of legs produced inside to 2 

 coarse diverging projections. Inner ramus of 2nd pair of legs large, and of a 

 structure similar to that in the male of A. debilis, the distal joint being exserted 

 at the end in a long mucroniform projection. Last pair of legs resembling in 

 structure that in the male of A. tenellus, but having the distal joint more ex- 

 serted at the tip. 



Colour whitish. 



Length of adult female 0.63 mm. 



Remarks. In its external appearance this species somewhat resemble 

 A. imus (Brady), exhibiting a similar very slender form of body. It is however 

 of much inferior size, and moreover differs in its less prominent rostrum and in 

 the structure of the natatory legs, which latter are built on the very same type 

 as in A. debilis. 



Occurrence. Some specimens of this form were found last summer together 

 with the 2 preceding species at Farsund, south coast of Norway. 



118. Amphiaseus sinuatus, G. 0. Sars, n. sp. 



(PL CXVIII). 



Specific -Characters. Female. Body moderately slender, resembling in 

 shape that of A. longirostris, though perhaps somewhat less robust. Cephalic 



