ADSTEALIAN CLADOCEKA. 



61 



The antennulae are relatively narrower and more elongate 

 than in A. Arclieri, reaching well-nigh to the apex of the ros- 

 trum, but for the rest exhibit a very similar structure. 



The antennae, oral parts and legs agree exactly with those 

 in the last species. 



The tail (fig. 6), on the other hand, exhibits very decided 

 differences. It is relatively shorter and broader, with the ex- 

 tremity transversally truncate, and has the supraanal angle much 

 less projecting than in A. Archeri, whence the tail appears about 

 of equal breadth throughout. The outer part of the dorsal edge 

 is armed with a double series of rather small denticles, about 

 10 in each row. They somewhat increase in size distally, but 

 the outer ones do not by far attain the large size characteristic 

 to A. Archeri, nor is there any trace of the secondary spinules 

 distinguishing those denticles in the said species. The caudal 

 claws are rather large, though relatively a little shorter than in 

 A. Archeri, and, as in that species, have at the base a slender 

 secondary denticle. 



Within the body occur numerous rather large oil-globules, 

 more especially along the intestinal tube, but their colour does 

 not differ from that of the body itself. 



The eggs discharged into the incubatory cavity are very 

 frequently two in number, and placed one behind the other, the 

 anterior generally with its longer diameter transverse to the 

 longitudinal axis of the shell (see fig. 5). 



The colour of the body is clear yellowish or corneous, the 

 shell itself being very pellucid and considerably paler than the 

 body within. The eggs, as recently discharged into the matrix, 

 have a bluish green colour, with a somewhat lighter circular 

 area in the centre. 



Biological Observations. — Of this species I observed during 

 the months of June and July 1886 a few rather small specimens 

 in 2 of my aquaries, prepared that year. The specimens did 

 not however mutiply to any greater extent, and subsequently 

 wholly disappeared. The next year (1887) another small aquary 

 was prepared with a parcel of the same mud, kept the winter 



