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THE VOYAGE OF H.M.S. CHALLENGER. 
Subfamily 2. Myctirinae. 
Myctiris, Latreille. 
Mydiris, Latreille ( Midyris ), Crust, in Cuvier, Regne Anim., ed. 1, vol. iii. p. 21, 1817. 
,, Milne Edwards (Mydiris), Hist. Nat. Crust., vol. ii. p. 36, 1837 ; Ann. d. Sci. Nat., 
ser. 3, Zool., vol. xviii. p. 154, 1852. 
Body very thick and dorsally convex, nearly smooth, with the cervical and cardiaco- 
branchial sutures strongly defined. There are no distinct orbits, but a small postocular 
spine. The front is very narrow and deflexed, and is triangulate or subacute at the 
distal extremity. The epistoma is very short and transverse. The post-abdomen in the 
male, as in the female, is broad, and widens from the base to the penultimate segment ; 
the terminal segment is narrow, and rounded at the distal extremity. The eyes are very 
short and exposed- in a dorsal view. The antennules and antennae are very small ; the 
antennae in particular very short and slender, and inserted beneath the bases of the eye- 
peduncles. The exterior maxillipedes project very markedly from the buccal cavity, and 
are closely applied to one another along their inner margins ; the ischium is largely 
developed and truncated at the distal extremity ; the merus is somewhat narrowed and 
rounded at the distal extremity, where it bears the following joint. The chelipedes (in 
the male) are slender and moderately elongated ; carpus and palm compressed, and 
usually carinated above, carpus usually longitudinally sulcated on the exterior surface ; 
palm very short ; fingers straight and acute ; dactylus with only one large tooth on the 
inner margin near the base. Ambulatory legs slender and somewhat elongated ; dactyli 
nearly straight, and not denticulated on the margins. 
The following species are referable to this genus, Myctiris longicarpus, White 
( = Myctiris brevidactylus, Stimpson ?), common on the shores of Australia, and occurring 
in the Malaysian subregion and at New Caledonia, and Myctiris platycheles, Milne 
Edwards ( = Myctiris subverrucatus, White), common in Australia. 
Myctiris dejiexifrons, a species mentioned by de Haan, has apparently never been 
described. 
Myctiris longicarpus, Latreille. 
Midyris longicarpus, Latreille, Gen. Crust, et Ins., vol. i. p. 41, 1806. 
Mydiris longicarpus(is), Milne Edwards, Hist. Nat. Crust., vol. ii. p. 37, 1837 ; Crust, in Cuvier, 
Regne Anim., pi. xviii. fig. 2 ; Ann. d. Sci. Nat., ser. 3, Zool., vol. xviii. p. 154, 
1852. 
Myderis longicarpus, Haswell, Cat. Australian Crust., p. 116, 1882. 
Mydiris brevidactylus , Stimpson, Proc. Acad. Nat. Sci. Pliilad., p. 99, 1858, var. 
Albany Island, near Cape York, North Australia. Numerous specimens, none of 
large size, were collected. 
