328 MR. J. R. HENDERSON— A CONTRIBUTION 



morning and evening, when the sun's rays are less powerful, and on the slightest sign 

 of alarm they at once seek their burrows. One species of this genus (O. cordimana) is, 

 however, a strictly terrestrial crab, and occurs at some distance from the sea, often living 

 among the matted branches of a trailing convolvulus, which is frequently also the 

 shelter of a sand-lizard (Mabuia Bibronii, Gray), and it may be seen even further 

 inland, inhabiting the sandy soil of casuarina plantations. Hiding in the sand at low 

 water, the curious anomurous forms Hippa asiatica and Albunea symnista are found, 

 the former in particular being very abundant. On the stonework of the harbour, and 

 in those few localities where rocks appear, species of Grapsus and Plagusia are seen 

 clinging tenaciously to the surface by means of their sharp dactyli, which enable 

 them effectually to withstand the force of the breakers among which they live. Outside 

 the surf-zone is a belt of shallow water, with the bottom composed chiefly of broken 

 shells and sand, in which the Crustacean fauna is undoubtedly rich. I have obtained 

 considerably over one hundred species from it, and there are certainly many more yet 

 to be discovered. All my gleanings from this helt come from the heaps of material 

 thrown up on the beach by fishermen, who practise fishing by means of very long nets, 

 taken out through the surf in catamarans, and afterwards drawn in on the shore. Here 

 are found species of Doclea, Egeria, Neptunus, Goniosoma, Matuta, Calappa, Philyra, 

 Dorippe, Diogenes, Themis, and Squilla, along with representatives of other genera in 

 smaller numbers. Indeed, it is scarcely possible to examine the shore-heaps without 

 finding the following species : — Doclea hybrida, Goniosoma vdriegatum, Matuta victrix, 

 Philyra scabriuscula, Dorippe facchino, Diogenes custos, and Squilla nepa, which are 

 certainly those found in greatest abundance. Grey and sombre hues prevail among 

 these species, which, doubtless, effectually protect them on a more or less sand-tinted 

 bottom, while the comparative absence of fragile forms — the fossorial ones excepted — 

 and the relative abundance of swimming species, e. g. Portunids, Matuta, and the curious 

 hermit-crab, Spiropagurus spiriger, indicate an exposed and turbulent habitat. In the 

 Madras fish bazaars numerous species of Pen&us, Palcemon, Panulirus, Neptunus, &c. 

 are exposed for sale, for among the lower orders of the community size is apparently the 

 sole criterion of edibility as regards Crustacea. The two edible species par excellence 

 among Europeans are the large swimming crab {Scylla serrata) and the prawn (Penceus 

 monodon), although some of the specimens sold under the latter designation belong to 

 the genus Palcemon, and come from fresh water. The so-called " river " Cooum, the 

 water of which is brackish only towards its temporary outlet, and everywhere much 

 contaminated by town sewage, affords shelter to species of Palcemon, Penceus, and other 

 Macrura. On its banks are seen the burrows of a large species of Sesarma (S. tetragona), 

 and the crab itself may frequently be observed near the openings of drains, while the 

 sand and mud-flats are honeycombed by species of Gelasimns. The tanks or freshwater 

 ponds, and even the wells, are inhabited by species of Palcemon, Telphusa, and Caridina, 

 the most conspicuous being the freshwater prawn Palcemon carcinus, which attains a 

 considerable size, and the freshwater crab, Telphusa Leschenaulti. The burrows of 

 Telphusse may be seen almost everywhere, except in the most arid situations. Though 

 the Madras coast is, by its physical conditions, peculiarly uusuited for dredging, 



