76 MADRAS FISHERIES BULLETIN [VOL. XVI, 



favour Siphonochalina much more than they do Suberites, probably 

 because their superior activity enjoys greater freedom in the larger 

 and less tortuous cavities of the former sponge. 



Corals and Gorgonoids are scarce, the handsome Juncella juncea 

 being the only conspicuous representative found. 



Specially characteristic are enormous numbers of the branched 

 parchment-like tubes of a fine Eunicid (E. tubifex, Crossland). 

 The empty tubes were made known to science years ago by 

 Professor Mcintosh from material received from Mr. E. Thurston, 

 Superintendent of the Madras Museum, but it is only in the present 

 year (1904) that the animal has been described and named. Quite 

 a host of smaller creatures settle upon the surface of the tubes — 

 hydroid zoophytes, polyzoa, and compound ascidians, together 

 with an occasional Lepas of a species not yet identified. The last 

 named is of interest in that in colour and outline its appearance 

 approximates so closely to a branch of the Eunicid tube that this 

 may be regarded as a striking case of mimicry or protective 

 adaptation to environment. 



Colonial masses of the delicate calcareous tubes of Filigrana 

 were met with and numerous species of the usual errant worms. 



Of Echinoderms, Ophiuroids, Antedon spp., and P. lincki were 

 abundant. Many of the Antedons appeared, as already noted, to 

 be commensal (?) with sponges and with Gorgonoids, while com- 

 mensal in turn with Antedon I found Decapods and Ophiuroids- 

 the former consisting of a small striped crab and a striped 

 Galatheid, the latter of a small, short-armed black Ophiuroid upon 

 an Antedon of the same hue. 



Small Cephalopods {Polypus spp.) were numerous ; polyzoa and 

 tunicates were universal. 



Occasional individuals of a large Pinna sp. were found lying 

 prone on the rock and much enveloped with sponge and tunicate 

 growth, barnacles and the like ; some bore pearl oysters of about 

 one year old. 



To the west of the Uti group of pars a large chank-bed is 

 marked. Here we found rock to be practically absent with a 

 corresponding absence of the faunistic elements noted above. In 

 their place were quantities of chanks {Turbinella piriim) and of 

 Pinna shells. The former were mostly small as is to be expected, 

 this being a recognized chank-bed and within easy reach of 

 Tuticorin. Many of the Pinna were dead shells ; those that were 



