Mr Menon, Notes on Semper s Larvae. 
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Notes on Semper' s Larvae. By K. Ramunni Menon, B.A., 
Christ’s College ; Assistant Professor, Presidency College, Madras. 
[Received 3 March 1902.] 
While examining the Madras Plankton during the months of 
September and October last I was fortunate enough to come 
across some specimens of the Anthozoan larvae originally described 
by Semper in 1867, and since then in greater detail by E. Van 
Beneden (1) As some of the stages obtained on the present 
occasion have not, as far as I know, been previously described, and 
further appear to me to be of some value in determining the 
phylogenetic relations of the Zoantheae, the group to which these 
larval forms undoubtedly belong, a few observations have been 
embodied in the following notes. I regret I have not been able 
to consult Van Beneden’s recent volume on the Anthozoan larvae; 
I cannot thus ascertain if any of these stages or observations are 
really new. 
I must here express my most grateful thanks to Prof. A. G. 
Bourne for enabling me to obtain a regular and abundant supply 
of Plankton material ; and to Mr A. E. Shipley, of Christ’s College, 
for communicating these notes for publication. 
Of Semper’s first larva — named Zoanthella, by Van Beneden — 
I obtained half-a-dozen specimens of a very early stage, and after 
a prolonged search succeeded in getting one of a much later stage. 
This was carefully preserved and cut into sections. Of the young 
specimens one was preserved and cut ; the others were kept in 
sea- water with a view to obtain later stages. This attempt proved 
a failure, as after a period of over a month the two which sur- 
vived were only a little more advanced than the earliest stage. 
The single specimen of the latest stage obtained measured 
nearly 8 mm. in length, and was about 3 mm. thick in the middle. 
It has a pyriform body with a circular mouth placed at the narrow 
anterior end (fig. 1); a small ventral lip projects forwards below 
the mouth, but there is no dorsal lip. I have not seen the aboral 
aperture mentioned by Semper, and do not believe any such exists 
in this larva. The whole surface of the body is covered by small 
cilia. The peculiar, iridescent, ventral, longitudinal band of long 
cilia, stretching from near the mouth to about a quarter of the 
animal’s length from the aboral end, beats in a slow, rhythmical 
manner from side to side and apparently plays only a subsidiary 
