LARVAE OF DECAPOD CRUSTACEA 



38s 



sixteen setae. Maxillipede 3, exopod with twenty-two setae. Legs 1-3, exopods with 

 numerous setae; endopods large, chelate, twisted. Legs 4 and 5 long, twisted, un- 

 segmented and unbranched. Pleopods large, without setae, on somites 2-5. 

 The gills, which are not well developed, are arranged as follows : 



The pairs of gills seem to represent one pleurobranch and one arthrobranch. The 

 formula does not correspond at all closely with that of the adult, but it is not inconsistent 

 with it. It is quite commonly the case that the arthrobranchs appear later than the 

 pleurobranchs. 



OTHER STENOPID LARVAE 



It is obviously impossible to determine at present which of the very marked characters 

 which distinguish the different larvae are generic and which specific, but I assume 

 provisionally that the median hooked process of abdominal somite 5, which is known 

 to be a character of S. hispidus and S. spinosus, is confined to the genus Stefiopus. I have, 

 then, two more larvae to refer to this genus. 



Stenopus species II (Fig. 4) 



Sts. 413, 710 



Stage I (Gurney, 1924, p. 134, fig. 54 A). Length 3-1 mm., including rostrum 

 0-8 mm. 



Rostrum very long, smooth, extending beyond antennules. Carapace without supra- 

 orbital spines, produced behind at posterior angle into a small spine. 



Abdominal somites i, 3, 4 with pleural spines. Somite 5 with procurved median 

 ventral process. No dorsal spines. Telson and appendages as in S. hispidus. 



Stage VI ?. Length 13-3 mm., including rostrum 4-1 mm. 



Carapace with very large supra-orbital spines, and large spines at posterior angles. 



Abdominal somite i with recurved pleural spines and dorso-lateral processes. Somite 

 3 without dorsal spine, and with small pleural spines. Somite 4 with small pleural 

 spines. Somite 5 with median ventral hooked process. Somite 6 very long, with 

 terminal dorsal spine and a small ventral pair of spines. Telson elongated, with a pair 

 of terminal spines and four long setae between. Uropods large, with numerous setae ; 

 exopod with outer apical spine. 



Antenna, endopod about half length of scale. Legs 1-3 with functional exopods; 

 endopods very small. Legs 4 and 5 very small rudiments. Pleopods absent. 



