294 THE SCHIZOPODA. 



surface with setae of the two distal joints of second pair in the main as in fully 

 developed specimens; third pair of legs almost rudimentary; branchiae rudi- 

 mentary. 



The three anterior pairs of pleopods with the endopod very small though 

 terminating in a seta and the exopods well developed; the two posterior pairs 

 are smaller, with the exopod setiferous while the endopod is rudimentary, with- 

 out any seta. — Telson more slender than in the preceding stage; its terminal 

 part between the inner postero-Iateral spines considerably produced, the terminal 

 margin transverse but shorter and with only five spines proportionately smaller 

 than in the preceding stage; the inner pair of postero-Iateral spines with the 

 proximal half a little broader than in the preceding stage and considerably broader 

 than the intermediate pair, which are more slender than in preceding stage. 



Length of the specimen described 3 mm. — It was taken at Sta. 4588, 

 October 12, 1904, Surface. 



Remarks. — The shape and setae of the two distal joints of the second 

 elongate pair of legs prove beyond doubt that the last-named specimen belongs 

 to Stylocheiron carinatum G. O. S. And a comparison between this specimen 

 and the specimen in the intermediate Furcilia-stage gives the result, that both 

 belong to the same species. And as nothing was known on the larval stages 

 of any species of the aberrant genus Stylocheiron I find it useful to give here what 

 I can, though the younger specimen is not well preserved. The larvae of S. 

 carinatum differ from those of Nyctiphanes, Thysanopoda, Euphausia, Pseud- 

 euphausia, and Nematoscelis by having no denticle on the lower margin of 

 the carapace; I think that this feature affords a good generic character; yet 

 it may be very possible that the hitherto unknown larvae of the genus Nemato- 

 brachion agree with Stylocheiron in possessing no marginal denticles. The 

 larvae of Stylocheiron agree, as might be expected, with those of Nematoscelis 

 (and probably of Thysanoessa) in having the two distal peduncular joints of 

 the antennulae more slender than in those of the other genera mentioned, but 

 they differ from the larvae of Nematoscelis by the shape of the frontal plate 

 and by having the dorsal keel of the carapace smaller and remarkably far behind 

 the middle. But judging from the two above-described larval stages of S. 

 carinatum the development and structure of the larvae of the genus Stylocheiron 

 seems to deviate but little from other genera of the order. 



