318 BULLETIN OF THE 



After the first moult the larva had the form represented on Plate IV. 

 Fig. 1. The general shape is very much like the adult, but all the feet 

 except the last pair are provided with an outer swimmiug branch. The 

 armature of the carapace is now as follows : two large spines in the 

 median dorsal line, the anterior of which lies over the base of the eye- 

 stalks ; one on each side near the anterior margin, on a level with the 

 eye-stalks ; all of these are directed forward and furnished with minute 

 recurved teeth on their lower sides ; in addition to these there is a small 

 antennal spine on each side of the carapace on the anterior margin on a 

 level with the base of the second pair of antennse, and a very minute 

 spine at the autero-inferior angle of the carapace just below the antennal 

 spine ; this is probably the branchiostegal spine in the adult. The ros- 

 trum is furnished with hairs on its upper edge in front of the anterior 

 dorsal spine. The peduncle of the first pair of antenna) is now divided 

 into three segments ; both the inner and outer branches have increased 

 in length. Tlie flagellum of the second pair of antennre (Fig. 2, r i) 

 exceeds the scale in length, and its distal half is divided up into six or 

 seven segments. The first pair of maxillipeds (Fig. 1, VI) are very 

 small compared with the Decapodal legs ; the second and third pairs 

 increase in length successively. The chelipeds {IX, X) are terminated 

 by a perfect claw, in which the process of the penultimate segment is 

 equal in lengtli to the dactylus ; both dactylus and the opponent process 

 are furnished with a few plumose setae. The exopod of the penultimate 

 thoracic limbs has now attained a size equal to that of the limbs in 

 front. The appendages of the abdomen {XIV- XVIII) are much 

 larger than before the last moult ; a small projection from the inner 

 border of the internal rami of the second to the fifth pairs (Fig. 5, s) is 

 the beginning of the slender stylet in the adult (Fig. 2G, s) ; both 

 branches are now furnished with long plumose hairs ; the inner branch 

 of the first pair (Fig. 4, r i) is rudimentary. 



One individual of the form just noticed died during the process of 

 exuviation in one of my aquaria. It sufficed to show that the larva 

 after the moult differed in no important regard from the antecedent 

 form. The tooth on the outside margin of the outer blade of the swim- 

 merets, which is so conspicuous in the adult (Fig. 29), is beginning to 

 a])pear (Fig. 8). The telson is still armed with three pairs of long 

 bristles (Fig. 8) ; within the inner pair are two of very minute size. 



Length, 8 mm. 



I failed to rear any of tlie larv-a) in confinement beyond this stage. 

 The next form in the series which 1 have met with is the one repre- 



