78 Transactions . — Zoology . 



Colour — various, greater part of body usually tinged with red but some- 

 times with blue, integument thick and more or less opaque. 



Length about J inch. 



Hab. Lyttelton Harbour. On seaweed, usually at roots of Macro- 

 cystis. 



This species is very peculiar in appearance and presents several points 

 of interest. 



The maxillipedes are shown in PI. II., fig. 2 d. Both the basos and 

 ischios bear plates, that of the former ending in two rounded teeth, that of 

 the latter rounded at the end and with its inner edge setose, the meros has 

 its distal portion produced externally in a rounded lobe past the extremity 

 of the carpus, the propodos has its distal and inner margins setose, the 

 setae on the inner margin being minutely serrate ; the dactylos is broad, 

 subtriangular, and nearly free from setaa. 



The peculiar chelate character of the second pair of gnathopoda of male 

 appears to be acquired only in fully-developed individuals ; in smaller 

 specimens they are subchelate, with the palm transverse, as shown in 

 fig. 2g; intermediate forms between this and the fully-developed form 

 shown in fig. 2/ are also found. At first sight the carpus appears to be 

 absent ; I believe that it is joined on to the propodos, but the evidence of 

 this is not quite satisfactory. The sixth segment of the pleon appears to 

 be absent, unless the part that I have described as the basal portion of the 

 last pair of pleopoda represents the sixth segment itself ; if this be the case, 

 the last pleopod will be represented only by a single rounded joint; in 

 either case it certainly bears the appearance of being rudimentary and 

 useless. 



Genus Montaguana. 

 (Montagua, Spence Bate, Cat. Arnphip. Crust. Brit. Mus., p. 54.) 



As the name Montagua was long ago used by Fleming for a genus of 

 Nudibranch Mollusca, I have altered the name of Mr. Spence Bate's genus 

 to Montaguana. 



Generic characters : — " The superior antenna? are as long as the inferior, 

 and not furnished with a secondary appendage. The mandibles are not 

 furnished with an appendage. The maxillipedes are pediform, unguiculate, 

 and without, or with only rudimentary, squamiform plates. The first pair 

 of gnathopoda are small, subchelate, the coxae not developed into a squami- 

 form plate. The second pair of gnathopoda are larger than the first, and 

 have the coxae very large, squamiform, deeper than the body, and produced 

 anteriorly, so as to cover the organs of the mouth ; the propodos is de- 

 veloped upon the same type as in the first pair. The pereiopoda are 

 subequal ; the coxae of the two anterior pairs are very largely developed, 





