ON CRISTISPIRA VENERIS NOV. SPEC. 511 



OCCCERENCE OF MiCRO-OeGANJSMS IN THE CRYSTALLINE StYLES 



OF Lamellibraxchs. 



Ill additiou to making an exainination o£ the crystalline 

 style of Venus casta, I searched for Cristispiras in the 

 styles of eight other species of Lamellibranch. All these 

 were also obtained from Tamblegani Lake. I found Cris- 

 tispira3 present in the style of only a single species — 

 Soletellina acuminata Desh. (July three individuals out 

 of eleven examined harboured the parasites, though a crys- 

 talline style was present in every individual. In one style, 

 all the Cristispira) were dead and degenerating when I 

 found them. 



These C r i s t i s p i r te in the style of S o 1 e t e 1 1 i n a a c n ni i - 

 iiata had been previously discovered by Di-. Willey (cf. 

 Dobell, 1910). On account of the small amount of material 

 which I obtained, I was unable to make any extensive 

 observations upon these organisms. The Cristispirte of 

 this species are small, and resemble C. interr ogationis 

 Gross, I found similar forms — possibly identical with these 

 — sometimes inhabiting the style of Venus casta, in com- 

 pany with the large C. veneris. As they were found in 

 relatively small numbers I have not been able to make a 

 careful study of them. I believe, however, that there can be 

 little doubt that they belong to a separate species, and are 

 not developmental forms of Cristispira veneris. The 

 occurrence of more than one species of Cristispira in the 

 same style has already been described by Schellack (1909) in 

 several Lainellibranchs (Ostrea, Tapes, etc.), and by Gross 

 (1910) iu Pecten. 



In some of the other molluscs which I examined, I found 

 that the crystalline style was infected Avith Bacteria. These 

 were not present simply as a few organisms — derived from 

 the gut contents — on the sitrface of the style, but permeated 

 the whole of its substance. In fact, the whole style appeared 

 to be a pure culture of the particular organism which was 

 inhabiting it. As far as I am aware, this has not been 



