a) 
Fam. Hymenosomatidae. 
1858. Hymenosomidae, Stimpson, Pr. Acad. Philad., p. 108 (54). 
1886. Hymenosominae, Miers, Challenger Brachyura, Reports, 
Vol. XVID pp: 275,279. 
1898. Hymenosomidae, Ortmann, in Bronn’s Thierreich, Vol. 
VV. PE. 2): p. 17166: 
1900. Hymenosomidae, Stebbing, Proc. Zool. Soc. London, 
p- 520. 
1900. Hymenosonudae, Alcock, Journ. Asiat. Soc. Bengal, 
Vol. DX Pte 2- spp. 205, 201, ° 205, 385. 
Ortmann transfers this family from the Catometopa to the 
Oxyrthyncha, considering that the sternal position of the 
male genital orifices is outweighed by other features, the form 
of the second antennae, the presence of a rostrum, and the 
longitudinal position of the first antennae. Alcock, con- 
sidering this transfer to be a decided mistake, although holding 
that the true position of the family is still doubtful, thus 
defines it :—** Small marine and estuarine Catometopes having 
a curious supeificial resemblance to some of the Oxyrrhynch 
crabs of the Inachine sub-family, a resemblance heightened 
by the fact that the epistome is sometimes nearly as long as 
broad. The palp of the external maxillipeds articulates near 
the antero-external angle of the merus, but as the antero- 
internal angle of the merus is sometimes truncated the 
true relations of the palp are often not quite clear; the 
exognath is slender and partly or entirely concealed. There 
are no orbits, and the eyes are exposed and little retractile. 
(Carapace thin, flat? triangular or sub-orbicular, not very well 
calcified, usually produced to form a_ horizontal rostrum. 
Antennular fossae shallow and ill defined. Antennal peduncle 
slender. Buccal cavern square, the ischium [third joint] of 
the external maxillipeds well developed). Male openings 
sternal.”’ 
Gen. Hymenosoma, Desmarest. 
1825. Hymenosoma (part), Desmarest, Consid. gén. Crustacés, 
pros: 
1829. Hymenosoma, Latreille, Regne Animal, Ed. 2, Vol. IV., 
p. 63. 
1837. Hymenosoma, Milne-Edwards, Hist. Nat. Crust., Vol. II., 
P- 35: 
