IflO PROF. J. D. F. GILCHRIST ON A 



of a brownish colour. This appeared first on the antenna?, occurring at 

 intervals along their length as in the adult. Pigment then appeared on the 

 large ocular spines behind the base of. the eyestalk, and finally on the abdomen, 

 legs and thorax. On the thorax it appeared first at the spots where the new 

 spines of the next stage are forming, giving the appearance of more spines 

 than are really present in this puerulus stage (PI. 16). This was very 

 apparent when the first shell was cast, this being seen to have only the few 

 spines already described, while the spines of the new cuticle are much more 

 numerous. The late stage of the puerulus has the external appearance, 

 therefore, of the post-puerulus stage, and this, as we shall see, has given rise 

 to some confusion between the two stages. 



The colour of the animal at this late puerulus and the beginning of the post- 

 puerulus stage is of course identical, and was as follows in the living state : — 

 The flagella of the antenna? had a series of dark rings at intervals, and, 

 between these, were yellowish white in colour, which was also the colour of 

 the second and third segments of the autennre. The antennules were of a 

 dark colour on the segments, yellowish between, and their extremities were 

 bright red. The large frontal spines were of a bright pinkish red colour, 

 the other spines greyish brown. This last colour was also found, usually in 

 the form of a patch or stripe, on the segments of the walking-legs, the joints 

 between them being a light yellow. The whole carapace, excepting the 

 spines, was also of a light yellow colour. The abdominal segments had 

 patterns of slaty purplish-brown colour, which was again seen on some of the 

 spines of the telson. 



The bright pink spots of the underside of the body, characteristic both of 

 the phyllosoma and the puerulus, begin to grow fainter at the time of the 

 assumption of the general coloration of the body above described, and have 

 disappeared completely by its completion. 



Both the late puerulus and post-puerulus stages have been found in the 

 sea in tow-nets, and these show a more marked and brilliant coloration, the 

 red pigment of the antennules and rostral spines appearing also on the walking- 

 legs. The general coloration is shown in Plate 15, drawn by Mr. Gr. Birbel 

 from a specimen just captured. 



In about a week after the puerulus was put into the tank the cuticle was 

 shed. Only one individual, however, survived this process, and this one died 

 soon afterwards. Most of them were able to free themselves completely 

 from the abdomimil region and the thorax, and. to a large extent, from the 

 appendages, but the gill regions seemed a source of trouble in getting rid of 

 the old cuticle. This partial ecdysis, however, had the advantage of rendering- 

 it possible to compare any particular part of an individual puerulus with the 

 part which succeeded it in the next stage. That this next stage was not a 

 repetition of the preceding, but involved a more or less marked meta- 

 morphosis, will bs seen from the following description of the changes involved. 



