292 THE SCHIZOPODA. 



lobes somewhat short and broad; of third pair of legs only the branchia is 

 discernible. 



The four anterior pairs of pleopods with the exopod well developed, seti- 

 ferous, while the endopod is very small with a single seta. Fifth pair of 

 pleopods small, with the naked exopod marked off. — The uropods reach con- 

 siderably beyond the middle of telson; the endopod is longer than the exopod. —  

 Telson tapers in breadth from the base to a little before the outer postero-lateral 

 spines ; the distal part is intermediate as to shape and spines between the earlier 

 larval stages and the fully developed specimens; in the earlier stages three pairs 

 of postero-lateral spines and seven terminal spines are found, while in the adult 

 the intermediate pair of lateral spines and all terminal spines are wanting; in 

 the specimen mentioned here the terminal margin is short with three spines, 

 the middle spine much shorter than the submedian spines, each of which has a 

 strong spiniform denticle on each side before the middle; furthermore, the 

 intermediate pair of postero-lateral spines are lost, while the inner pair are 

 extremely broad, \'ery long and furnished with a number of fine spines on the 

 major proximal part of the inner margin. 



The specimen described is 3.5 mm. long. 



Remarks. — The shape and tegument with spines of the first pair of thoracic 

 legs proves that the specimen — taken at Hyd. Sta. 3789, Lat. 2° 38' N., long. 

 137° 22' W., September 9, 1899, Surface — belongs to the genus Nematoscelis; 

 furthermore among the species of this genus it must, according to the shape of 

 the eyes and the strong development of the dorsal keel, belong to either N. 

 microps G. 0. S. or N. gracilis H. J. H. And judging from the very high and 

 anteriorly steep dorsal keel I have referred it to N. microps. 



Whether the specimen described shall be referred to the last Furcilia-stage 

 or the first Cyrtopia-stage is almost a matter of free choice. But it may be of 

 some interest to compare it with the above-described larva of Euphausia dis- 

 tinguenda. In both larvae the four anterior pairs of pleopods are setiferous, 

 the thoracic legs are nearly equ ally developed and the end of the telson has only 

 three marginal spines, but in E. distinguenda the intermediate postero-lateral 

 pair of spines which have been lost in Nematoscelis, are still preserved, while, 

 on the other hand, the antennular flagella are very short and unjointed in the 

 latter, but somewhat elongate and three-jointed in the former species. This is 

 a new instance of the above-mentioned fact that as to the consecutive order 

 of the development of appendages and telson considerable differences are found 

 in this order. 



