StiKlics iin iii;itiiie Ostiaroils 4'>1 



has no bristles. TJie bristle of the second joint is powerful and is abcjut the total length of the 

 seven distal joints; ventrally it is furnished with short, stiff secondary bristles but has no spines; 

 only in exceptional cases (cf. A. aberrata) arc these secondary bristles relatively long; distally 

 it has a fine point. The bristles on the third to the eighth joints are long, powerful natatory 

 bristles, some of which are sometimes almost double the length of the exopodite. These bristles 

 have rather long but comparatively narrow natatory hairs and are furnished with short spines 

 along a large part of the ventral side; these spines are as a rule rather strong on the proximal 

 natatory bristles, very weak on the distal ones; in a number of species I have even been quite 

 unable to observe them on the most distal of these bristles (with Reichert's oc. 4, Leitz' imm. 

 V12) (quite missing?). The end joint has three or four bristles, two of which are developed as 

 long natatory bristles. On these two, which always seem to be somewhat shorter than the other 

 natatory bristles, I have succeeded in observing, at least in some cases, weak ventral spines; 

 in most cases, however, there seem to be no spines at all on these bristles. These two bristles, 

 like the other natatory bristles, are furnished distally with a short, fine hair, but apart from 

 this they are not differentiated* as specific sensory organs. The two remaining, dorsal, bristles 

 of the end joint have short hairs but have no spines; one of them is often about as long as the 

 total length of the four or five distal joints, the other is somewhat shorter; one of them 

 may sometimes be quite absent. The fourth to the ninth joints — less frequently the third 

 to the ninth — are each often furnished with a basal spine. These spines are often broadly conical; 

 the one on the ninth joint is the largest, being sometimes about as long as this joint, the others 

 decrease more or less uniformly in size and strength the more proximally they are attached, the 

 proximal one being in most cases rather weak, somtimes even scarcely perceptible. In a number 

 of species, however, the number of basal spines is reduced, sometimes they are even quite absent. 

 Distally-dorsally on the second to the eighth joints there is a series of hairs, in most cases verv 

 short and rather coarse, or of weak spines; on one or more joints, differing in different species, 

 they are sometimes not inconsiderably longer than on the other joints. On the first joint there 

 were observed in most of the species described in this work one or two transverse rows of fine, 

 rather short hairs dorsally near the distal boundary. The endopodite is more or less 

 clearly three-jointed and has only one bristle, the distal bristle of the end joint; this bristle is 

 closely and finely annulated, of about uniform thickness and is rounded distally. Sometimes 

 a short bristle was observed distally on the second joint; this was obviously abnormal. 



Male: — Both the p r o t o [) o d i t e and the exopodite are considera bly 

 more strongly developed than in the female. Exopodite: The proportions between the 

 joints are somewhat different from those of the female (cf. the descriptions of the species). The 

 bristle of the second joint is considerably lengthened, but it is not quite so long as the natator\- 

 bristles on the nearest joints. The end joint has three long natatory bristles, as one of the short 

 bristles of the female is rather considerably lengthened — but not quite so long as the natatt)rv 

 bristles of the nearest joints — ami is provided with well-developed natatory hairs. In species 

 with four bristles on the end joint the fourth bristle is also somewhat longer than in the female 

 and is provided with well-developed natatory hairs. The natatory bristles on the third to the 

 ninth joints are also somewhat longer than in the female. .Vll the bristles are without anv spines. 



