7o 



several times as long as broad with at most a few hairs; third joint half as long as, and not 

 narrower than, the second, with numerous setae. Maxillulae (fig. i^-) normal. Maxillae (fig. \ Ii) 

 normal ; terminal joint of the palp two and a half or three times as long as broad. Maxillipeds 

 (fio". i i) without epipod or exopod, robust, with numerous setae and some among them thick ; 

 second joint almost parallel with the median line (fig. i d), with a somewhat small lobe (fig. i ?'), 

 third joint as broad and at the inner side almost half as long as the second, without lobe; 

 sixth joint with four strong terminal spines behind the insertion of the seventh joint, which is 

 as long, but not half as broad, as the sixth; claw strong. The interval between the maxillipeds 

 and the gnathopods longer than the distance from the gnathopods to the last thoracic legs. 



The gnathopods (figs. i a and i d) very long, as long as the carapace, and extremely 

 thick; fifth joint a little longer than the sixth, which is widened towards the oblique end against 

 which the seventh joint terminating in a strong claw is bent about as in the first pair of legs 

 in Crangon (sens. lat.); the exopods have the second, long joint extremely slender. Thoracic legs 

 extremely long and slender ; sixth joint divided by two vertical articulations, the proximal one 

 a little beyond the middle; seventh joint somewhat small, terminating in a fine claw; exopods 

 with the subbasal joint extremely slender. The female marsupium consists of two pairs of lamellae. 



At least the five anterior abdominal segments with some less or more developed teeth 

 or spiniform processes on the hind margin above and on the sides; sixth segment at most 

 somewhat longer than the fifth. Female pleopods (fig. i /) short, cylindrical styles. Male pleopods 

 well developed, essentially as in Erythrops, but none of the setae on fourth pair seem to show 

 any peculiarity. Uropods very slender, without spines, but their setae very long, especially on 

 the ends of the rami; endopod even slightly longer than the exopod; otocyst small. Telson 

 not one-third as long as the uropods (fig. i k), with the end truncated, short. 



Remarks. — This genus, which presents a quite peculiar aspect, is, as already stated 

 by Holt & Tattersall, allied to Chunomysis Holt & Tatt., but cliffers at least in the shape of 

 the eye-stalks and eyes and in the great distance between the maxillipeds and the gnathopods. 

 Furthermore Holt & Tattersall do not state whether the maxillipeds in Chunomysis possess 

 epipod and exopod or whether both are wanting as in Arachnomysis or perhaps at least an 

 epipod exists; finally the endopod of the gnathopods, and especially its distal part, differs very 

 considerably in the two genera. Holt & Tattersall have established the subfamily Arachnomysinse 

 on the purely negative character that a squama is wanting in its two genera, Chunomysis and 

 Arachnomysis, but this artificial classification I can not adopt. Chunomysis, which differs less 

 from the other Mysinae than Arachnomysis, is allied to Ccesaromysis Ortm., which possesses an 

 extremely small, styliform squama, thus constituting a connecting link between Chunomysis and 

 more normal forms of the Erythropini. Furthermore it may be pointed out that the peculiar 

 shape of the distal part of the gnathopods in Arachnomysis is only a higher development of 

 a feature already perceptible in Euch&tomera typica G. O. S. and E. Vogtii Chun. And for 

 these reasons I think it better not even to establish Arachnomysis itself as a tribe, but to refer 

 it lo the Erythropini. 



Hitherto Arachnomysis comprised only a single species, A. Leuckartii Chun, from the 

 Mediterranean. The "Siboga" collection contains a single specimen of a closely allied species. 



