47 



the use of the dredging steamer " Violet''' at that time, I was able to satisfy myself 

 by actual experiment that the dredge is an efficient implement for successful chank 

 fishing. 



The bottom where the Parmandadai took the " Margarita " was quite unlike that 

 of any of the undoubted chank beds we had previously visited, while the depth of 

 water, almost ten fathoms, was nearly double that upon typical chank beds. 



The ground was extremely rich in life, elongated cylindrical actinians of two 

 species were abundant embedded in the sand, together with large numbers of an 

 elongated Molgulid, which appears to live upright with the aboral extremity 

 implanted in the sand. A small Flabellum sp. was plentiful on the surface together 

 with a drab and grey Pennatula and many Yirgularia jitncea ; asborescent rosy tipped 

 Pennatulids were also characteristic, while several specimens of a hollow-stemmed 

 coarsely-branched Aleyonarian (? Siphonogorgia sp.) were taken. The latter were 

 pink and white in colour and were accompanied in each case by a pair of small crabs 

 and a pair of small Galatheids similarly coloured and obviously commensals. 



Some colonies were more uniformly suffused pink than others and on these the 

 commensals were more uniformly tinted pink. On one colony, where white colouring 

 largely prevailed, and where the margins of the branches alone were coloured pink, 

 the crabs were uniformly white except for two splashes of pale pink on the anterior 

 edge of the carapace. The large fan-shaped green alga with bulbous base embedded 

 in the sand was the only alga found. A single specimen of Lingula sp. was one of 

 the noteworthy acquisitions made in this locality. 



The sand was fine, clean, and with no trace of the mud which is a characteristic 

 component and essential attribute of a prolific chank bed. 



Hence we moved north to the Tolayirarn Par, where we anchored after verifying 

 the locality by cross bearings and by some trial dives, which indicated the presence 

 •of numerous young oysters. 



During the evening the crew caught a large number of trigger fishes {Batistes) 

 and of strong-toothed fishes of the genus Lethrinns, the latter being known as 

 Tellamin * among the Tamil fishers. The stomach contents of the Batistes were in this 

 case free from incriminatory evidence in respect to pearl oysters, due probably to the 

 fact that all the individuals were of a small size. In the case of the Vellamin on the 

 contrary the stomachs were crammed with fragments of pearl oyster shells upon which 

 this fish appeared to be feeding exclusively. As six of these, all of large size, were 

 caught within two hours it is plain that these fish are now inflicting enormous havoc 

 npon the bed of oysters on this par. 



The next morning I donned the diving dress, and the water being fairly clear 1 

 had an excellent opportunity of examining the bank. 



The depth where the descent was made is 9| fathoms. I found the bottom very 

 variable ; in most places a covering of about an inch and-a-half of sand lay upon flat 

 surfaced rock. Here and there the rock protrudes or lies level with the general sandy 

 surface. These exposed patches are small in area, usually from 1| to 2 feet in 

 diameter. A. limited amount of small cultch is present on the surface to which the 

 majority of the oysters adhered. The cultch consists of short fragment of much 

 worn branches of coral (" ehullai"j, quite small Nnllipore balls (Lithothamnion), the 

 tests of dead echinoids (chiefly of Clypeaster humilis)^ fragments of calcrete and such 

 like. 



The oysters were fairly abundant, their numbers obviously curtailed by the 

 quantative limitation of the cultch. They appeared to be of two generations, the one 

 four to five months, the other ranging from six weeks to two months. 



Sponges were not obtrusive, several specimens of the peculiarly massive Petrosia 

 testudinaria were seen but the commonest species was one which interiorly is yellow, 

 while the exterior is more or less tinted with pale green. In its growth it envelopes 

 much sand in its substance, which is generally level with the sand surface, sending 

 up stout tapering branches at intervals. Its general appearance is inconspicuous. 



• ZetJtrinus ntlulosut arid other species-. 



