•il-l Dr. W, T. Caiman oyi the Genus Puerulus and the 



Among the Palinuridje collected by Dr. C. W. Andrews, 

 F.R.S., on his recent visit to Christmas Island are five 

 specimens presenting the characters of '■''Puerulus spiniger^'' 

 Ortmann. They are all about 25 mm. in length of body, and 

 were collected partly on the reef and partly in crevices in the 

 ]»ilcs of the pier at Flyincr-Fish Cove. In all of them the first 

 four pairs of legs have, on the outer side of the basipodite, 

 a soft shrivelled process, which is no doubt the vestige of an 

 exopodite. Tiie antennular peduncle is much shorter than 

 the antenna! ; the third maxillipeds are widely separated 

 at the base, and the other mouth-parts are soft, without 

 setffi, and imperfectly formed ; the appendix interna of the 

 pleopods has an apical group of coupling-hooks. In all these 

 characters tlie specimens agree with those described by Boas, 

 and I see no reason to dissent from his conclusion that they 

 represent a late stage, which may perhaps be called post- 

 larval, in the development of a species of Palinurid. 



I believe, however, that it is possible to go further, and to 

 assign these specimens, with considerable confidence, to the 

 species Panulirus versicolor (Latreille) *. As in the case of 

 the specimens described by Ortmann from Amboina, those of 

 the present collection were found together with young indi- 

 viduals of the species just named, some of which do not 

 exceed the ^^ Puerulus" form in size (25 mm.). The smaller 

 specimens of the Panulirus differ from the larger (up to 

 74 mm. in length) in some small details of structure, e. g. in 

 having the antennular peduncle shorter instead of longer than 

 the antennal, in which they resemble the Puerulus-ioxm. 

 They also differ from the larger specimens in the less brilliant 

 colouring, the bright purple being replaced, in the smaller 

 spirit-specimens, by brown, and the longitudinal striping of 

 the legs being undeveloped. The general pattern of the 

 coloration remains, however, the same. Ortmann describes 

 [loc. cit.) the " Jugendfarbung " of this species, mentioning 

 especially a W-shaped marking on tlie carapace formed by a 

 longitudinal white band on each side, and a pair of bands 

 converging to the middle line from the hinder ends of these. 

 He notes that in specimens of i&D and 33 mm. length this 

 pattern w^as no longer visible. It would, perhaps, be more 

 correct to say that the converging bands lose their importance 

 as the colour-pattern increases in complexity, although they 

 can still be recognized even in very large specimens. The 



* As defined by Pfeffer, " MittL. Mus. namburg " (Jalirb. Ilamb. wiss. 

 Anst.) xiv. pp. 255 & 262 (1897;. 



