160 



The sub-median skeleton without processes, but the part obliquely inside and behind the 

 base of the maxillae is covered with pretty numerous seta?. Shape and hair-covering of the 

 lateral margin of the head nearly as in S. dispar; from its posterior extremity the boundary 

 of the hairy part proceeds at first vertically upward across the side of the animal, then 

 somewhat obliquely backward across the back. The back and sides of the trunk and the 

 posterior part of the ventral surface are closely covered with rather long hairs, nearly all 

 the remainder of the ventral side has hairs of medium length. Trunk-legs and caudal 

 stylets wanting. 



OVISACS. In D. Icevis they were small, almost globular, with few eggs; in D. 

 comuta they differed considerably in size, from rather small to middle-sized, and were irregular 

 on account of mutual pressure. Eggs of medium size. 



LARVA. There is no appreciable difference between the larvae found in D. Icevis 

 and in D. comuta. A well- developed free larva from D. comuta is '20 mm. long and has 

 served as type for fig. le — lg. It bears great resemblance to S. dispar, but is sharply 

 distinguished by several characters. The cephalothorax like that of the last-mentioned 

 species. The decoration of the front is very characteristic (fig. 1 f) : a transverse list is found 

 inside the base of the antennulae; further, a sinuate transverse series of processes, with a 

 broad central interruption, runs from one antennula to the other; the inner half of this 

 series begins far behind the frontal margin, below the anterior side of the rostrum, thence 

 it continues in an oblique direction running forward and outward towards the margin, 

 consisting only of five or six longer processes; then comes a little break in the row, the 

 next process being somewhat further removed from the frontal margin, after which the row 

 is continued to the anterior angle of the antennula, but in its latter part the processes are 

 shorter than the sub-median ones. The olfactory seta of the antennulae is even longer than 

 in S. dispar, as, when bent backward, it may reach as far as the posterior end of the 

 second abdominal segment. Antennae and maxillulae as in the preceding species. Second 

 joint of the maxillae without setae (fig. lg), third joint with three or four processes on its 

 inner margin, the outermost of which is longer than the curved extremity of the joint, but 

 scarcely longer, at least not considerably so, than the penultimate process. The abdomen 

 and its setae as in the preceding species. 



POST-LARVAL DEVELOPMENT. In D. comuta a single pupa was found (fig. 1 h), 

 which is 14 mm. in length and sub-globular. It is described in detail above on p. 56. 



HABITAT. The marsupium of Diastylis comuta Boeck and D. Icevis Norm, from 

 Denmark. In a specimen of D. comuta were found : an empty skin of one female, one male 

 and seven small ovisacs with young ones in different stages, as well as twelve free larvae 

 and one pupa. In one specimen of D. Icevis occurred an oblong lump of adhering ovisacs 

 surrounding a female; they were irregularly shaped on account of pressure; on one side of 

 the lump the larger part of one side of the female was uncovered, and on the side turning 

 towards the abdomen of the host, there was a longitudinal impression in the lump, in which a 



