108 DR. J. D. F. GILCHEIST ON LARVAL AND 



These phyllosomas at first sought the light rather quickly, and crowded in a 

 dense mass to a corner of the tank, which at certain times was well lighted. 

 Later, they were found throughout the water at all distances from the 

 surface, and some of them were observed to seek the bottom and come up 

 again. A number, at about the same stage of development, were put in a 

 small glass vessel for better observation, and it was very easily seen, by 

 altering the source of illumination, how readily they sought the light. For 

 about six days they swam about in the tank and then disappeared. Towards 

 the end of that period they seemed to avoid the light. To make certain of 

 this, an active and healthy specimen was carefully watched in a small jar, 

 and it was observed that, in about seven days, it began to avoid the light, 

 and could be made to pass from any one part to another by illuminating the 

 jar from various sides, but, whereas it at first sought the light, it now as 

 obviously avoided it. This behaviour may have been due to abnormal 

 conditions, but, taken in conjunction with the marked absence of later stages 

 among the many thousands caught by the tow-net, would seem to confirm 

 the suggestion that the phyllosomas go to the bottom after this stage. They 

 may do so at each ecdysis. 



Phyllosoma of 3-8 mm. [Fig. 21] PI. 15. 



The phyllosoma nearest the first in point of size is a single specimen, 

 procured 50 miles south-east of Table Bay, by a tow-net on the beam of a 

 trawl, working at a depth of 230 fathoms. It is somewhat imperfect, 

 anteunules and the distal end of the third maxillipede being broken off; the 

 other features resemble those of the phyllosoma of 1*7 mm. 



The endopodite of the antennce is relatively large and has a distinct division 

 halfway between the origin of the exopodite and the base of the flagellum. 

 The exopodite is relatively smaller, being now only about half the length of 

 the endopodite. The parts immediately surrounding the mouth (upper lip, 

 mandible, lower lip, and maxillce) are, so far as could be made out, similar to 

 those of the first phyllosoma, but in relation to the cephalic shield, which has 

 now grown very large, occupy a relatively small area of the under surface, 

 the distance between the outer edges of the maxillae being contained about 

 5 times in the breadth of the shield, in place of about 3 times, as in the 

 first phyllosoma. 



The second maxillce are not different from those of the previous stage. 

 They are slightly larger, being 0*16 as compared with O'll mm. in the 

 first stage. 



The first maxillipede seems to be entirely absent. 



The second maxillipede resembles that of the previous stage in relative 

 length of segments and in arrangement of setse. 



The third maxillipede has the first four segments in the same proportion as 

 before, and there is as yet no trace of an exopodite. 



