120 



of the male in its posterior and lateral parts shows the peculiar feature (mentioned above 

 on p. 42) of large, hollow spaces beneath the skin (fig. 4 k). 



The first pair of trunk-legs are long and consist of one branch, and it is no doubt 

 the outer branch which is preserved (sometimes even it appears to be set off by an articu- 

 lation); the peduncle is long, proximally rather large, partly hairy; the branch ends in a 

 seta which is nearly as long as the whole leg. The second pair of legs consist of a shorter, 

 cylindrical basal part and a somewhat longer, a little more slender, cylindrical branch, which 

 terminates in a seta which is even considerably longer than that of the first pair of legs. 

 The caudal stylets are thick, their terminal seta being even longer than that of the second 

 pair of legs, and about half to more than half the length of the whole animal. — The male 

 is frequently found hinged by a frontal thread (fig. 4h, s) which measures about three eighths 

 of the length of the body, and the distal part of which dilates gradually towards the end. 



OVISACS. They are oblong, varying from a moderate to a very large size: the 

 specimen represented in fig. 4d is -69 mm. in length and -50 in breadth; it contains rather 

 numerous eggs which are comparatively large. 



LAEVA (fig. lc). Length -22mm. The body slender; the cephalothorax about 2 /s 

 longer than broad; the front with an oblique list inside the anterior angle of the antennulae. 

 Antennulae 2-jointed; olfactory seta comparatively short, less than double the length of the 

 antennula and about a third of the length of the cephalothorax. Antennae considerably 

 shorter than the antennula?, the first joint (comp. fig. le, for in fig. lc there is a fault in 

 the engraving) pretty thick, of the same length as the second one, third joint short, and 

 the terminal seta equalling in length the two last joints combined. Of the maxillulae we 

 find the posterior branch and one of the anterior branches in the shape of long setae, the 

 hindmost of which is naked, and close in front of its base is seen a rather small conical 

 process (fig. le), which is a rudimentary branch. Maxillae and maxillipeds normal, with 

 smooth joints. Abdomen chiefly as in S. Calliopii; however, the last segment and the 

 caudal stylets which are distinctly set off, are a little larger, but the terminal seta is 

 scarcely so long, a little more than half the length of the animal. 



POST-LARVAL DEVELOPMENT. The attachment of the larva and subsequent 

 great change of form (fig. 1 d), as well as the highly interesting development, is described in 

 detail above, p. 57 — 58, to which we refer. 



HABITAT. The marsupium of Bathyporeia norvegica G. 0. Sars, B. pelagica Sp. Bate 

 and B. Robertsonii Sp. Bate from Denmark. In a considerable material I found altogether 

 eleven infested specimens, two of which are B. norvegica, iomB. pelagica and five_B. Robertsonii 1 ). 



l ) G. 0. Sars, in his excellent work: "An Account of the Crust, of Nonvay, Vol.1", admits altogether five 

 species of Bathyporeia from Norway and the Baltic. Of these species B. norvegica G. Sars and B. gracilis 

 G. 0. S. are decidedly good, and well distinguished from the three others, but whether these three species 

 can be maintained, or have to be reduced at least to two (in regarding B. pilosa Lindstr. as a freshwater- 

 form of B. pelagica), perhaps even to one, is difficult to decide, and must be submitted to a new, thorough 



