294 
THE VOYAGE OF H.M.S. CHALLENGER. 
Subfamily 1 . Hepatina;. 
Hepatinse, Stimpson, Bull. Mus. Comp. Zool., vol. ii. p. 154, 1870. 
Carapace somewhat cancroid in form, with the antero-lateral margins arcuated, the 
dactyli gressorial, not natatorial. 
Genera: — Hepatus , Latreille; Osachila, Stimpson; Actseomorpha , Miers. 
This subfamily is not represented in the Challenger collection. 
Subfamily 2. Matutina. 
Carapace usually suborbiculate ; the dactyli of the eight posterior legs natatorial, i.e., 
with the dactyli laminated and dilated. 
Genus : — Matuta, Fabricius. 
Matuta , Fabricius. 
Matuta, Fabricius, Entom. Syst. Suppl., p. 369, 1798. 
,, Milne Edwards, Hist. Nat. Crust., vol. ii. p. 113, 1837. 
„ Miers, Trans. Linn. Soc. Lond. (Zool.), ser. 2, vol. i. p. 243, 1877. 
„ de Man, Notes Leyden Mus., vol. iii. p. 109, 1881. 
Carapace much depressed, and usually very slightly broader than long, with the 
antero-lateral margins slightly arcuated and irregularly dentated or tuberculated, and 
terminating in a strong acute lateral spine (which in Matuta inermis is reduced to a 
tubercle) placed at the junction of the antero-lateral and postero-lateral margins. Front 
narrow, about equalling the orbit in width, with a projecting median lobe, which is 
sometimes entire, sometimes notched. The dorsal surface is usually armed with six 
tubercles, placed, three in a median transverse series, one, anterior, on each side of the 
gastric, and one, posterior, on the cardiac region, and there is also usually a tubercle on 
the postero-lateral margin. The orbits are rather large, with a hiatus, communicating 
with an excavation on the subhepatic region, below the exterior orbital angle. Antennules 
nearly longitudinally plicated. Antennae very small, and placed below the enlarged basal 
joint of the antennules, with the flagellum obsolete. The exterior maxillipedes cover 
the whole of the buccal cavity; their ischium -joint is distally truncated, the merus 
triangulate and distally subacute, and covers the following joints ; the exognath is ex- 
ternally arcuated and reaches but little beyond the distal extremity of the ischium of the 
endognath. Chelipedes subequal, robust, and closely applicable to the body, with the 
merus trigonous, carpus externally slightly tuberculated, palm armed with spines or 
tuberculated ridges, fingers distally acute, the dactyl usually with a tuberculated or 
striated ridge on its exterior surface. Ambulatory legs of moderate length, with the 
joints compressed, the penultimate and terminal joints in all laminiform and dilated ; in 
the fifth legs the dactyl is oval as in the Portunidse. 
