48 Records of the Indian Museum. [Vol. \'I, 



horizontal rather than vertical. Although they do not actually 

 twine round one another, they are so confused in their twistings that 

 it is impossible to isolate a single shell from the mass ; the length 

 of the longer shells, measured along their loose and irregular whorls, 

 would be considerable, if it could be accurately measured. 



It is not my intention to give a technical description either of 

 this shell or of the other Vermetidae mentioned in these notes, for 

 they all represent well-known species and are admirably figured 

 by Reeve in vol. xx of his Conchologia Iconica. Mr. H. B. Pres- 

 ton has identified the ridged species as Siliqiiaria muricata (Born.), 

 but this species is believed by some authorities to be synonymous 

 with S. anguina (lyinn.). The mollusc is, in any case, widely dis- 

 tributed in Indo-Pacific seas. 



The sponge associated with our specimens of S. muricata is 

 identical with a species recently described from the Gulf of Manaar 

 by Dendy under the name Spongosorites topsenti. The original 

 specimens were not associated with Siliquaria shells, but one of 

 them had grown over calcareous nodules and it is probable that 

 the sponge makes use of any suitable support, living or dead, in 

 its growth. As I have already stated, the colour of the speci- 

 mens before me is an intense black. These specimens are dry, 

 and there is evidence that they were dark green when fresh. 

 The shells are of a dirty white, so that there is considerable 

 contrast Ijetween them and the sponge. The latter fills up the 

 spaces between the shells and covers the greater part of the base 

 of the mass but leaves the distal part of the shells free, as a rule 

 for several inches. As it possesses no definite skeleton, the sponge 

 would not persist for long after its death, for the spicules to which 

 its hardness is due would soon fall apart. 



The masses of the second series may be further divided 

 into two groups. At first sight the)'' resemble one another closely 

 as regards structure but are easily distinguished by colour. A 

 closer examination, however, reveals the fact that colour is asso- 

 ciated with structural peculiarities, and that we are dealing with 

 different species of shell and with sponges that exhibit certain 

 idiosyncrasies correlated with those of the shells with which they 

 are associated. In those masses in which the sponge is red, yellow 

 or orange, the shell is extremely delicate and fragile, has a lus- 

 trous appearance and is at no point tightly coiled, while the sponge 

 is not very massive. In those in which the sponge is grey diver- 

 sified with purple the molluscs have thicker shells which lack the 

 lustre of those in the other masses and are more tightly coiled, 

 while the sponge is more compact. The shells of the first kind have 

 been identified by Mr. Preston as those of Spiroglyphus cunimingi 

 (Morch), a species originally described from the Philippines; those 

 of the second kind he has named Siliquaria cochlearis, Morch. 

 this species having originally been described from Ceylon. 



It will be convenient in the foUowing notes to refer to the 

 denser masses as the Siliquaria-m.asses, to the others as the 

 Spiroglyphus-masses ; but it should be noted that Siliquaria and 



