528 TAOK SKOC.SHKHO 



slioll tluT*' is a iiUHlpratc miinbiT nt tatlicr short bristles, airmiucd in a siiij^lc distiiRt row. 

 Posteriorly, somewhat in front of tin- spine-benring list, this row Ix-conies very dense and at the 

 sjinio tiini' the liristles become longer and coarser; it ((intiniies u|) aloni; the ventral i|iiarter oi- 

 third of the spine-bearing list, running about half way lietween the lattei- and the niaruin of 

 the shell (fig. 5). The spine-bearing list has rather few hyaline spines, about 1!>— IJU, of somewhat 

 varving size, and has a sparse row of siiort bristles, about one or two ])etween each hyaline 

 spine. The double line drawn in tig. 5 inside the posterior margin of the shell corresixmds to 

 a sharp ridge; the part of the shell between this ridge and the posterior margin of the shell is 

 situated rather considerably laterally — i.e., when the shell is looked at from inside, it is consid- 

 erably deeper — of the part between the ridge and the spine-bearing list; a ridge of this sort 

 is characteristic for both the valves. Just inside the dorsal half of this ridge there is a sparse 

 row of broad pores (six such pores were always observed on the specimens investigated); in the 

 specimens investigated these pores did not seem to be furnished with low hyaline pegs. In 

 addition a rather dense and irregular row of fine pores issues near this ridge. 



First antenna (figs. 6 and 7): — This is very like the corresponding limb in 

 A. Grimaldi. We may note: It is seven-jointed, the third and fourth joints are not united to 

 each other. Of the six anterior bristles on the third joint no. 5 has short hairs. The a-claw 

 on the end joint is only shghtly longer than the anterior side of the fifth and sixth joints; it has 

 only extremely weak pectination dorso-proximally. The f-bristle has five, the c- and g-bristles 

 six or seven sensorial filaments. The first and second joints are rather abundantly furnished with 

 hairs; the second joint, however, as in A. Grimaldi, has no row of hairs along the distal boundary. 



Second antenna (fig. 9) : — Very like that of A. Grimaldi. The p r o t o p o d i t e 

 has a short bristle disto-medially close to the exopodite. Endopodite: On one specimen 

 this was abnormally developed on one side, reminding one very much of this branch in the 

 male in the penultimate larval stage; the second joint had a very small bristle near its distal 

 boundary; the bristle of the end joint was displaced somewhat proximally (fig. 10). 



Mandible (fig. 11): — Protopodite: Coxale: The scythe-shaped process 

 (fig. 12): The part situated distally of the main spine grows narrow rather rapidly, but 

 not so rapidly as in A. Grimaldi, into a fine point; its ventral edge is slightly concave 

 distally and slightly convex or almost straight proximally; it forms, just near the main 

 spine, a rather weak spine which points proximally. The distance between the point of the 

 process and the main spine is rather slightly shorter than the distance from the latter to the 

 proximal ventral spine. The dorsal bristle is fixed somewhat nearer the main spine than its 

 distance from the point of the process, and somewhat, though only rather slightly, distally of 

 the main spine; it extends rather slightly beyond the point of the process. The dorsal serrate 

 teeth are rather few in number, but comparatively large. The main spine is rather strong. There 

 are four ventral spines, the two distal ones of which are rather weak, the two proximal ones 

 rather strong. Between the distal ventral spine and the main spine the ventral edge is finely 

 serrated; the serrate teeth point proximally; this serration may sometimes be more or less 

 completely missing — presumably on account of wear. On the part distally of the main spine 

 there are onlv a few — two or three were observed — transverse rows of hairs. The rod-shaped 



