2^ Journal of the Asiatic Society of Bengal, [Jantiary, 1907. 



the slender stems and roots of Avater-plants. In spite of their 



small size, some of tliem tad evidently persisted long enougli for 

 a new layer of skeleton and sarcode to he formed on the top of 

 one in which numbers of gemmules had been produced. Each 



gemmule. is enclosed in an irregular basket- work of skeleton 

 spicules. 



As regards the generic position of this and the succeeding form 

 some doubt may be expressed. ^Trochosporiyilla, as accepted by 

 Weltner, is differentiated from Tuhella, by the fact that the discs 

 of the birotulates are both equal and entire. In the present 

 instance they are often both equal and entire; but at least as 

 often the outer disc is distinctly, if yery slightly, smaller than the 

 inner. In Trochospongilla Indyi, lioweTer, which, as I agree with 

 Weltner, is a trne Trochospcngilla, this is also the case, so far as 

 can be judged from Pott's figures (]'roc. Acad. Set. PMladephia, 

 xxxiv., pi. xi., fig 1.) In Yejdovesky's original definition of 

 the genus, the birotulates are described as having discs which 

 are "smooth with entire margins "; no mention is made of their 

 equality or inequality. As regards most of the genera into Avhich 

 the " sub-family " SpongiUinae has been divided, it is difficult to 

 draw exact lines of demarcation ; indeed, in most cases, one 

 geniis merges gradually into another. It might be well to 

 regard Ephydutia, Trocho-p.nyiUa, Tube' la, Heferomeymia, and 

 possibly Oa^tertus as no more than sub-genera of the genus 

 Mei/ema; but the bpongiUinae, as a whole including all the fresh- 

 water genera ) form a group so ill-defined that great difference of 

 opinion IS inevitable as to their sub-division. 



No species of the genus TrocliospomnUa has hitherto been 

 Recorded from Asia. I name T. latonchuma after Mr. T. Latouche, 

 ot the Geological Survey of India. 



TrOCIIOSPONGILLA PfllLLOTTIANA, sp. nov. (Fig. 6.) 



ovpv^flr^^ f?*' encrasting, very thin, spreading in large patches 

 over flat surfaces, almost colourless ; surface minutely hispi*, 



Fig. G. TrocJiospovgilla phillottiana. 



Spienles, x about 370. 



I 



pores and oscula inconspicuous Slcplpfnn a,.;^ i 



gilt or almost straight, 16 to 18 ti 



mes 



