1908.] Records of the Indian Museum. ■ 173 



however, that, in order to include it, the definition of this genus 

 must be modified, and that it is very difficult to draw an exact line 

 between Lophopus and Pectinatella, if the younger stages of the 

 colonies of the latter are to be taken into account, and if the Indian 

 forms are to be placed in the former. Moreover, the Japanese forms 

 {Pectinatella gelatinosa and P. davenporti) do not altogether agree 

 with the only other fully described species of their genus, viz., 

 P. magnifica of N. America and the continent of Europe, Unfor- 

 tunately I have not yet been able to obtain a copy of the full 

 account of P. davenporti, which is published by the Japanese 

 Zoological Society, and am therefore forced to rely on the 

 summary thereof published by Oka, the author of the species, in 

 the Zool. Anzeiger, vol. xxxi, No. 23, May, 1907. Mr. Rousselet 

 has, however, drawn my attention to the close similarity between 

 th^ statoblasts of this form and those of L. carteri. 



Further, there is a certain biological resemblance between 

 L. carteri and the species of Pectinatella. Oka {Journ. Coll. Sci. 

 Tokyo, iv, 1891) has described P. gelatinosa as forming gigantic 

 compound colonies by the coalescence of numerous small zoaria, 

 each of which arises from a single statoblast ; and a somewhat 

 similar phenomenon occurs in P. magnifica. I found large numbers 

 of small zoaria of L. carteri, grouped together but quite distinct 

 from one another, on the under surface of stones in the lake at 

 Igatpuri in November last. They were apparently adult zoaria 

 and most of them bore mature statoblasts. When they were 

 detached from their support, however, and placed in a bottle of 

 water, several of them coalesced so as to become, to the naked eye, 

 a single colony, although a microscopic investigation revealed the 

 fact that it was only the gelatinous investment that had taken 

 part in the coalescence. Such compound colonies did not 

 appear to be permanent, nor did I see any in natural conditions. 

 Moreover, they showed no tendency to secrete a common basal 

 membrane, as the components of the large colonies of Pectinatella 

 do. 



On the leaves of a tree whose branches dipped into the water 

 of a lake at Kawkareik in the interior of the Amherst district of 

 Tenasserim I found, in March last, a number of similar zoaria, 

 quite independent of one another. They differed from those taken 

 in the Bombay Presidency in autumn in the following characters : 

 (i) their coenoecium had a decided yellow tinge ; (2) their poly- 

 pides were larger ; and (3) they bore no statoblasts. It is just 

 possible that these were young colonies of the form described below, 

 on the evidence of a statoblast from the same lake, as Pectinatella 

 burmanica; but their zooecia were upright and the histological 

 similarity between them and zoaria of L. carteri was so close that 

 I think they must have represented this species. If they belonged 

 to the same species as the statoblast found in their vicinity, it 

 would, in my opinion, be impossible any longer to separate the two 

 genera ; but this is a point on which it is not yet possible for me 

 to express a definite opinion. 



