320 
THE VOYAGE OF H.M.S. CHALLENGER. 
width. The channel defined by the endostomian ridges is not emarginated distally. 
Post-abdomen (in the male) narrow, and at base covering the sternum between the fifth 
ambulatory legs, with all the segments except the first and last coalescent. Antennules 
nearly transversely plicated. Antennae with a rather slender basal joint which does not 
quite attain the front. The triangulate merus-joint of the endognath of the exterior 
maxillipedes is shorter than the ischium ; the exognath is of moderate width, and its 
exterior margin is nearly straight. Chelipedes rather robust and short, and shaped 
nearly as in Lithadia and Oreophorus, with the merus granulated, palm rather short 
and turgid, fingers compressed and denticulated on the inner margins, but the denticles 
are not spinuliform. Ambulatory legs short and granulated, with the dactyli styliform 
and somewhat uncinated. 
But a single species has as yet been recorded of this curious genus ; Merocryptus 
lambriformis, A. Milne Edwards, whose types were from Upolu. 
Merocryptus lambriformis, A. Milne Edwards. 
Merocryptus lambriformis, A. Milne Edwards, Journ. Mus. Godeffroy, vol. i., Heft 4, p. 85, 
pi. ii. fig. 1, 1873. 
Bass Straits, off East Moncoeur Island, 38 fathoms (Station 162), several males and 
females; off Twofold Bay, 150 fathoms (Station 163a), two small males. 
In the smaller males the gastric and cardiac prominences, and the tubercles of the 
posterior margin, are more prominent and acute than in the adult and fully-grown 
specimens. 
The largest male measures as follows : — 
Adult £ . Lines. Millims. 
Length of carapace, . . . . . . . 4J 9'5 
Breadth of carapace, exclusive of lateral lobes, rather over 4 9 
Philyra, Leach. 
Philyra, Leach, Zool. Miscell., vol. iii. p. 18, 1817. 
,, Milne Edwards, Hist. Nat. Crust., vol. ii. p. 131, 1837. 
„ Bell, Trans. Linn. Soc. Lond. (Zool.), vol. xxi. p. 299, 1855. 
This genus is nearly allied to Leucosia, but distinguished by the less convex carapace, 
which is usually granulated or punctulated, but not polished ; by the broader front, which 
is not at all prominent, and usually slightly concave ; by the absence of the sinus 
thoracicus, and by the form of the exognath of the exterior maxillipedes, which is usually 
much more dilated, and is rounded at the distal extremity, with the exterior margin 
arcuated. 
