105 



species, is shorter than the peduncle and terminates in two setae, one short, the other longer 

 or somewhat shorter than the peduncle plus the branch, and finely plumose; the outer process 

 terminates in a short seta. The branch — at least in most cases — is not distinctly set 

 off from the peduncle by an articulation; if nevertheless this seems to be the case sometimes, 

 it may be owing to an optical delusion. The second pair of legs consist of a rather short 

 and slender peduncle and two branches, the outer of which is short, conical and terminates 

 in a short seta, the inner one agrees with the branch on the first pair of legs and terminates 

 in similar setae 1 ) (the outer branch is never set off by an articulation). The caudal stylets 

 are comparatively long, with a seta which is shorter than the stylet and proceeds from its 

 inner angle. — The animals are sometimes hinged by a frontal thread (pi. II, fig. 4 b), the 

 very complex structure of which is described above on p. 42-43. 



OVISACS. They are ovate, in the large species of comparatively medium size, in the 

 small ones very large compared with the females, and in the small species the female probably 

 lays only four to five, in the largest species as many as ten ovisacs (possibly even more). 



LARVA. Known in only two species: S. elegantula and S. antillensis (pi. Ill, 

 fig. 2e); the latter is the one described here. Cephalothorax seen from below, a somewhat 

 elongate oval. On the front, inside the base of each antenuula, two lists, running so as to 

 form a somewhat acute angle, but they do not quite meet. Antennulae 3-jointed, the olfactory 

 seta reaching a little beyond the middle of the cephalothorax and measuring less than three 

 times the length of the antennula. Antennae somewhat longer than the antennulEe and 

 specially characteristic by consisting of four joints of sub equal length and a terminal seta 

 which is longer than the two last joints together, or about as long as the three last joints. 

 Of maxillulae only two naked branches have been found. Maxillae rather robust. Maxilli- 

 peds of scarcely medium length, second and third joints of about sub-equal length. Peduncle 

 of the natatory legs moderately slender. Abdomen proportionally short and broad; the long, 

 stout seta at the posterior angle of the first segment reaches far beyond the extremity of 

 the caudal stylets; third segment very short, and the not defined caudal stylets also short, 

 their terminal seta more than three quarters the length of the cephalothorax. 



POST-LARVAL DEVELOPMENT. Very peculiar; we refer to the description 

 given above on p. 58 — 60. 



HABITAT. All my eight species were found exclusively in fully developed marsupia 

 which contained no eggs or young ones of the host. Salensky states that his S. LeucJcartii 

 were found both in females and in males, but the latter, no doubt, were young females 

 (comp. above, p. 66—67). 



*) For a long time I considered the branch on the first pair of legs to be not the outer but the inner 

 one, and the conical process to be the outer branch of the leg, but a comparison with some of the other 

 species (e. g. S. Metopce and S. Giardii) will prove the interpretation adopted to be correct. Perhaps the 

 interpretation of the branches of the second pair of legs will not prove to be correct, but for the present it 

 is impossible to decide this question with any certainty. 



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