Polyzoa Entoprocta and Ctenostomata. iq 
on the Gulf of Siam ; at the edge of the lake in water of very variable salinity but 
having a specific gravity (corrected to a standard temperature of i5°C) of i 00625 at 
the time when the specimens were taken. The type-specimen was attached to a 
stone that had been built into a sea-wall. It was accompanied by colonies of Bower- 
bankia caudala and of the Cheilostomes Memhranipora hippoptts and M. hengalensis. 
ECTOPROCTA. 
Order Gymnolaemata. 
Suborder Ctenostomata. 
Farmer's recent account of the Ctenostomata of the 'Siboga' Expedition ' has 
done much to elucidate the internal relationships of this very difficult group, and 
although I have not been able to accept all his conclusions on the families of fresh and 
brackish water (which naturally do not come fully into view in the consideration of 
the results of a naval expedition) I must here express my indebtedness to this admir- 
able work, which has done for the seas of the Malay Archipelago almost as much as 
Hincks' British Marine Polyzoa did for those of Great Britain. In saying this I do 
not of course mean to infer that the Polyzoa of that vast area in the East are as well 
known as those of British seas were even in Hincks' time ; but there is now a soHd 
foundation on which further study can be based. 
The suborder is well represented among the Polyzoa of fresh and brackish water 
in eastern lakes and ponds, but until recently our knowledge of the anatomy of 
critical genera has been very scanty, mainly owing to the fact that a number of the 
more important forms, though easily preserved in formalin or alcohol, collapse and 
become valueless if transferred to oil of cloves or cedar. It is thus very difficult to 
examine stained specimens under a high power of the micioscope, without the aid of 
which I find it impossible to ascertain details with certainty. Harmer {op. cit., p. 41) 
gives elaborate directions, based on the methods put forward by Rousselet, for the 
mounting of specimens in formalin for microscopic examination, but specimens so 
prepared, though often both beautiful and useful, cannot be satisfactorily used under 
really powerful objectives. Moreover, the methods are so elaborate, tedious and 
costly that it is difficult to mount a sufficiently large number of preparations in the 
case of variable forms. I find it necessary, in the case of species like those of Vic- 
torella and Bowcrbankta, to examine not several but many preparations and to search 
in all for details that cannot be seen unless the organisms are stained and rendered 
transparent, and also, if not flattened, at any rate rendered as flat as maybe possible 
without distortion. For this purpose a simple modification of Rousselet and Harmer's 
technique is sufficient, though I cannot say if it is permanent; the preparations will 
last, in a tropical climate, at least for two or even three years, and possibly for longer. 
I place the specimens to be mounted, after staining with borax carmine and 
cleaning in acid alcohol, in a 50 % solution of glycerine in 70 % alcohol and leave 
1 Siboga-Expcditie. Monograph XXVIIIa. The Polyzoa of the Siboga Expedition. Pt. I. Entoprocta, Ctenostomata 
and. Cyclostnmata (Leiden, 1915). 
