4r)'2 T\r.K SK'OOSIiKIUi 



and the basal sjjines arc very mvicli reduced. J)orsally-distally on the sccoiid to the eightli 

 joints there is a cluster of rather long, fine hairs. E n d o p o d i t e: TJie cud joint is rather 

 decidedly curved and is somewhat more than half the length of the second joint; it can be folded 

 back against a, corresponding furrow on the second joint. The first joint has no bristles at all. 

 The second joint has (always?) three bristles ventrally at about two-thirds or three-quarters 

 along the joint. The end joint has a single bristle proximally on the outside; this bristle is of 

 about uniform thickness and is rounded distally. 



Mandible: — 



Female: — This is relatively short, but is very powerfully built, with its joints 

 decidedly flattened at the sides. The proportions between the joints are about the same in all 

 the species investigated by me and aie illustrated by the following figures (from measurements 

 carried out on a specimen of A. noroegica, ?): 



I Pr. :;:'• II Tr. ,!.;; 1 EmI. '„'; II Knd. !!; Ill En 



Protojjodite: Coxale: This has no bristles. The endite issues from, or jx'rhaps it would 

 be more correct to say ft)rms basally, a chitinous list, which extends transversely across the joint; 

 cf. G. 0. Sars, 1887, pi. IV, fig. 4. The scythe-shaped process is uniformly and moderately 

 strongly curved in two planes, partly upwards, partly inwards, and is, in addition, slightly 

 twisted so that its medial side is turned somewhat upwards; it is thus turned towards the mouth, 

 in which 1 often found it inserted (already observed by G. W. MULLER; cf. 1894, p. 46). On the 

 distal part of its ventral edge there is always a more or less strongly developed spine, pointing 

 proximally, characterized by the fact that it is continued by a low ridge, in most cases rather 

 short, on the lateral side of the process. This ridge forms a curve which is concave proximally 

 and is furnished, like the spine, with a close series of rather short, fine, stiff spines, pointing 

 proximally. ProximaDy of this spine there is along the ventral edge of the process a number 

 — in most cases rather small — of protuberances or spines ; these are most frequently somewhat 

 difi'erent in number and type in different species; within the species they are certainly not 

 constant, but their variation is not so great that they cannot to some extent serve as a character 

 for the species; I often found them rather strongly worn, which may, of course, modify their 

 appearance considerably. From some of these spines a series of low protuberances runs in 

 a dorso-proximal direction on the lateral side of the process; in a number of species these pro- 

 tuberances are rather numerous, in others they are more or less sparse; in addition they are 

 also subject to some variation within the species. Distally of the middle the dorsal edge is often 

 serrated along, in most cases, a rather short part; the teeth vary in size, in some species they 

 are even almost completely reduced. The dorsal edge is, in addition, distinguished by a single 

 bristle, in most cases rather long, which is situated almost opposite or somewhat distally of the 

 above-mentioned proximally jjointing spine on the ventral edge of the process. On a great part of 

 the surface of the process there are numerous striations, generally speaking parallel to each other, 

 of which the distal ones at least are furnished with close, extremely short and fine hairs pointing 

 distally; these hairs are scarcely perceptible even with very strong magnification (Rkichkrt's 

 oc. 4, Li;iT/'.s innncrs. -). Similar sti'iations, running across the process in distally concave 



