ijS Miscellanea. [VoL. I, 1907.] 



In Calcutta the species has only been found on the leaves of 

 Valisneria spiralis. 



In describing the form of the colonies, Dr. Annandale says 

 that, in Calcutta " the linear arrangement is far commoner than any 

 other, but occasionally several zocecia are adjacent to one another 

 in a transverse series " A somewhat similar arrangement to this 

 " linear " one also occurs at Bulandshahr, though it is much rarer 

 than that next to be described. I have found a few small colonies, 

 of perhaps twenty to thirty zooecia growing in this way on slender 

 submerged leaves and twigs, where the colony has not room to 

 extend much laterally. But in this part of India (the United 

 Provinces) Hislopia is far more frequently found in the form of a 

 flattened encrusting sheath on the outer surface of the shells of 

 Paludina and at least one other freshwater Gastropod. This was 

 the condition described originally by Carter {Ann. Mag. Nat. Hist. 

 (3), i, page 169). 



The colony consists of a single layer of zooecia, and completely 

 covers the whole surface of the shell with the exception of the narrow 

 surface which lies in contact with the upper part of the protruded 

 " foot " of the Mollusc. Almost every Paludina that I have ex- 

 amined carries Hislopia about with it, and as Paludina occurs very 

 abundantly, Hislopia is by far the commonest of the Polyzoa met 

 with in this part of India. 



The zooecium of the encrusting form is of a darker brown 

 colour than the other ; in both varieties the colour is most marked 

 at the margin of the orifice. 



Carter describes the shape of the zooecium as " irregularly 

 ovate." This oval shape is decidedly more marked in the encrusting 

 than in the linear form. The orifice always occurs nearer the broad 

 than the narrow end of the oval, and projects further above the 

 surface of the zooecium in the encrusting form. Very few of my 

 specimens show spines at the orifice, and those that do bear spines 

 have them in a more or less rudimentary condition. As this occurs 

 in large zooecia, which contain eggs, I cannot think that the absence 

 of spinesiis a sign of immaturity. 



I fully agree with Dr. Annandale' s remarks about the nature of 

 the " valves/' and my observations do not confirm the statement 

 made by Carter (quoted by Annandale, loc. cii.) that the posterior 

 " valve " is larger than the others. 



As noticed by Carter and Dr. Annandale, the " collar " is a 

 very conspicuous part of the polypide. 



Although when reduced to writing, the differences between the 

 two forms of Hislopia do not appear to be very great, I think that if 

 only the dried colonies were available for examination, there would 

 be a strong tendency to regard them as distinct species at least. 

 But the living polypides appear to be identical in form, and 

 there is little doubt that the two quite distinct phases in which 

 Hislopia occurs are merely another example of that variability 

 which is well known to occur in other Polyzoa, such as Plumatella. 



H. J. WAI.TON, Capt., I. M.S. 



