im TACK sKOf;snr;nr, 



situated distallv. K x i> p (m1 i t i^: \'«'r\ inovably joined to the protopodite, with which, in 

 a position of rest, it forms a decided, ventrally open knee; developed into a powerful, long, 

 cvlindrieal. (always?) 9-jointed locomotive organ (in all the species of this group investigated 

 by me for this treatise I constantly found idne joints); almost always used for swimming. Its 

 first joint always extended, forming distally-laterally a powerful, almost rectangular process 

 which extends over the base of the second joint (functions as a ratchet), is either entirely without 

 bristles or has distally-ventrally an extremely short and weak one. The succeeding joints grow 

 narrower the more distallv they are situated; the distal one is very small; at least the six distal 

 ones of them are short; the second to the eighth joints each have a bristle distally-ventrally 

 and somewhat medially; on the third to eighth joints these bristles are long and powerful, 

 annulated along the greater part of their length; most of them most frequently provided with 

 natatory hairs arranged in feather shape; the bristle of the second joint generally rather long, 

 powerfid, annulated, in exceptional cases almost completely reduced; the end joint has distally 

 more than one bristle, one of which at least is long and powerful. A greater or less number of 

 the distal joints have a more or less powerful spine situated ventrally-distally and somewhat 

 laterally. Endopodite: Always considerably shorter and weaker than the exopodite; 

 of a rather varj'ing type, with never more than three joints; sometimes more or less reduced 

 in one or both sexes. In the male often developed into a clasping organ by which the female 

 is held fast; never used as a locomotory organ. 



Mandible: — This is always very powerful, and elongated, chiefly used for crawling 

 and digging. Protopodite: This is always two-jointed. The coxale, which is fixed at the 

 sides of the body just behind the second antenna, has most often a comparatively weak endite 

 directed backwards-dorsally (used only for inserting the food into the oesophagus, never as 

 a masticatory organ?); this endite is sometimes, however, entirely absent. An endite is sometimes 

 found on the basale in the A s t e r o p i d s, but there is usually no well-developed one; traces 

 of an endite in the form of an accumulation of bristles proximally-ventrally-medially on this joint 

 can most often, however, be stated to exist. Epipodial appendage always 

 absent. Exopodite: Is fixed distally-dorsally-laterally on the basale, always more or 

 less diminutive (reduced?), unjointed, often including the openings of a powerful gland; some- 

 times entirely absent. Endopodite: Is always powerful, 2 — 3-jointed, forming together 

 with the protopodite a decided knee open downwards. 



Maxilla: — Very varying in type; always used in taking up food. With a well- 

 developed endopodite. Its exopodite always more or less reduced, sometimes even 

 quite absent. E p i p o d i t e sometimes developed, forming a lameUiform appendage, most 

 often with fine hairs and quite without bristles. 



Fifth limb: — Similarly of very various types, always used in taking up food. 

 Fixed at the sides of the body, just at the boundary between the head and the body. Always 

 with a relatively short exopodite. Endopodite often not developed. With a large 

 and powerful oval epipodial appendage developed as a vibratory plate, attached 

 vertically to the protopodite along its whole length and furnished with very numerous 

 marginal bristles, not divided into distinct groups; these bristles are furnished along 



