5Q 



increasing in length and thickness to or beyond the middle, where they are very strong ; the 

 terminal portion of the spines without any lateral armature. 



Length of both sexes 10 mm. 



Remarks. — This species, which shows much resemblance to Siriella, is one of the 

 most interesting forms of Mysidacea secured by the "Siboga". It may be convenient to remark 

 that the state of preservation did not allow a more detailed description of the distal part of the 

 thoracic legs. - The species is easily distinguished from P. flagellipes Illig (from the estuary 

 of the Congo) by much shorter eye-stalks. 



Subfamily IV. Gastrosaccince Norm. 



The characters of the subfamily is given in the synopsis on p. 11 — 12. The subfamily 

 was established in 1892 by Norman for the genera Gastrosaccus Norm. and Anchialus Kröyer; 

 he saw that these two genera, though differing much as to general aspect, are in reality related 

 to each other. In 1906 the same author substituted the name Anchialina for Anchialus, which 

 was preoccupied for a genus of Coleoptera. Kossmann in 1S80 established the genus Haplostylis, 

 which in my opinion cannot be maintained as well separated from Gastrosaccus-, the same is 

 the case with Pontomysis Czern. established in 1882. Chlainydopleou Ortm., established in 1893, 

 is also to be cancelled, being founded on a species closely allied to Gastrosaccus spinifer Goës. 

 Archaomysis Czern., established in 1882, is to be maintained, because the pleopods of the 

 female, though very small, are all biramous; the genus is nearly related to Gastrosaccus. The 

 genus Callomysis, established by Holmes in 1895, is probably identical with Archcsomysis, 

 having the "pleopods in the female rudimentary but biramous"; Holmes described and figured 

 the exopod of the uropods as setose along the outer margin, but I suppose it to be an error, 

 as that margin probably is furnished with a row of feebly curved spines as in Gastrosaccus and 

 ArcJucoiuysis. In the following I establish two new genera, Paranchialina and Pscudanchialina, 

 on two species described by G. O. Sars in his "Challenger" work and by him referred to 

 Anchialus; the genera Anchialina, Gastrosaccus and Pscudanchialina are represented in the 

 "Siboga" collection. Probably no other genus established in the literature belongs to the 



present subfamily. 



Anchialina Norman. 



{Anchialus Kr., preoccupied). 



Description. — Body stout. Carapace long, covering the thorax at most with the 

 exception of the posterior half of its last segment ; postenor margin straight or feebly emarginate ; 

 frontal plate somewhat or very much produced. Eyes well developed ; eye-stalks somewhat 

 short. Antennular peduncle much thicker in the male than in the female; the male lobe short, 

 tuberculiform ; outer flagellum in the male much expanded at the base. Antennal squama small, 

 short ; its outer margin naked and terminating in a denticle ; second joint of the endopod very 

 much longer and thicker in the male than in the female (PI. VII, figs. 3 c — $d). Mandibles with 



