236 Transactions. — Zoology. 



This species was obtained by Dana from coral-reefs at the Fijis, and 

 described as above. 



Numerous specimens of a form almost ideutisal with Dana's species were 

 obtained by me in Paterson Inlet with the dredge. They differ in having 

 the palm of the second pair of gnathopoda rather oblique and furnished 

 with irregular dentations (see pi. XVII., fig. 4a), and in the fifth pair of 

 pereiopoda being rather longer than the fourth. The length varied from 

 ^ to I of an inch, and all were of a uniform yellowish-white colour. 



Another form of the same — apparently variable — species was obtained 

 under stones, between tide-marks, from the same locality. Besides being 

 of slightly larger size, it was of a dirty green colour, and had the teeth of 

 the palm of the second gnathopod more sharply defined, in this respect 

 resembling the typical form (see pi. XVII., fig. 4b). 



A third form, with a more sharply defined palm still than the last, and 

 witli longer spines and numerous hairs on the propoda of the second gnatho- 

 poda, was taken by the dredge in Port Pegasus from a depth of 5 fathoms. 

 (Origmally described by Dana from Fiji specimens). 

 2. M. petriei, n.sp. 



PI. XVIIL, fig. 3. 

 Coxse not so deep as then- respective segments. Fourth segment of pleon 

 produced into two acute spines on its postero-dorsal margin, and having its 

 postero-inferior angles also acutely pointed. Eyes oblong, black. Superior 

 antennce as long as the body ; peduncle having its first joint as long as the 

 second, but twice as broad, third short ; secondary appendage shorter than 

 last joint of peduncle, about 6-jointed ; flagellum subequal with peduncle, 

 very many-jointed (about 50-60), joints at first more than twice as long as 

 broad, all setose. Inferior antennse less than half as long as superior ; 

 flagellum about 14-jointed, half as long as the peduncle. First pair of 

 gnathopoda having the carpus and propodos subequal, the latter oblong, 

 with an ill-defined oblique convex palm and a slender curved dactylos ; 

 dense rows of hairs occur on the extremity of the meros, and transversely 

 on the lower side of the carpus and margins of the propodos, while the latter 

 also bears numerous obhque or transverse rows of short spine-like hairs. 

 Second pair of gnathopoda very large ; basos deeply hollowed out in front, 

 so as to form a groove for the propodos ; ischium, meros, and carpos very 

 short, the latter about three times as broad as long ; propodos large, ovate, 

 distally produced into a large curved tooth on each side of the articulation 

 of the dactylos, terminal half of the lower surface with a deep groove to 

 receive the dactylos, whole lower surface very densely fringed with two rows 

 of long simple hairs ; dactylos strong,, arcuate, sinuously toothed on its 

 inner margin, blunt. First and second pairs of pereiopoda slender, three 



