Report on Larval Grabs. 9 



On the fii'st third of the dorsal spine there is a himinous yellow spot ; 

 the last third of this spine is deeply tinted with red. The lateral spine also 

 is i^ed, and red pigment is to be seen on the lateral region of the carapace 

 in front of the lateral spine. There is a bright yellow spot and a large 

 amount of black pigment in the mouth region. 



Bright luminous yellow spots are present on the latex'al region of 

 each abdominal segment. When the abdomen is seen in front view 

 the yellow spots form a luminous line mid-ventrally. The later larvae 

 got in the plankton show a beautiful red colouration, and exhibit this line 

 very characteristically. 



Later Zo'ea (^Plankton). 



This Zoea was comparatively lax-ge. It had a large quantity of red 

 pigment. The i-ostral spine had a slight pink colouration. On the 

 proximal half of the dorsal spine there were two small patches of yellow. 

 The bases of the antennae and the region of the labrum were a deep red. 

 Two widely-ramifying red corpuscles were prominent on the side of the 

 carapace, one in the inferior hind lateral region, the other at the base of 

 the lateral spine. The latter pigment-mass was accompanied by a black 

 corpuscle. The lateral spine was coloured yellow at its base, red in its 

 distal half. At the base of the dorsal spine there was a large quantity of 

 diffuse yellow. One or two minute yellow luminous spots were seen 

 anterior to the dorsal spine and one or two laterally. Red pigment was 

 visible on the ventral aspect of the retina, black or bluish- black above. 



On the abdominal joints there was yellow pigment accompanied by 

 black and red. The two latter colours were little in quantity, and were 

 situated on the joints. The yellow, which was concentrated at the joints, 

 ramified over the sides of the segments. At the anus there was a large 

 quantity of deep red pigment. The prongs of the telson were red in 

 colour. The first portion of the intestine was red. 



The general colouration seen by reflected light resembled the stain 

 of an aqueous solution of eosin. When the Zoea was resting on its 

 rostral and dorsal spines — in other words, upside down — the luminous 

 yellow spots on the mid- ventral region of the abdomen showed as a bright 

 line to the naked eye. When the Zoea is preparing to cast, the red colour 

 seems to lose a certain amount of its brightness. 



Colours oj Preserved Larvce. 



Some of the I. Zoea of puber, hatched in the Laboratory, were preserved 

 in formaline. Ten years later they presented the following appearance : — 

 The retinal portion of the eye was amber-brown. The pigment along the 

 abdomen, specially noticeable in the anal region, was a dark-brown, nearly 

 black. In the other segments there was. a strip of pigment along the 

 ventral edge, and some on the sides in the anterior half of the abdomen. 

 The bases of the maxillipedes were pigmented dark brown. Some brown 

 pigment was seen about the mouth appendages. 



Zo£A Stages. 



With the exception of the first Zoea, all the stages of Zoea and Megalops 

 were obtained from the plankton. The specimens belonging to this species 

 were easily recognised by the pigmentation. 



/. Zoea, fig. 4 ; Abdomen, fig. 45 ; Telson, fig 47 ; 

 Carapace, fig. 49. 



This Zoea resembles much the I. Zoea of Pm'tunus holsatus in general 

 tructure. 



