18C9.] and Membranipora Bcngalensis. 59 



dark string visible, and the rest was filled with a clear fluid 

 (fig. 1 i ). Whether this difference is due to different stages of growth 

 I am not in a position to say. I have not observed their develop- 

 ment in the present species, but I hope to recur to this subject at some 

 future occasion, when treating of the development of some of our fresh- 

 water Bryozoa. 



The microscopical structure of the animal is a granular, or cel- 

 lular substance in which numerous greenish pigment cells are inter- 

 spersed. There is no trace of cnidce, such as described in the Actiniacea 

 and Acalephcd. The tentacles generally are moved about slowly, not 

 being usually widely separated from each other, and the move- 

 ments of each are independent from those of the other, they also 

 often have the tips bent outward, (see fig. 1, g, pi. XII). It is 

 generally stated that the tentacles of all the Bryozoa are tubular, but 

 in the present species it always appeared to me, that they are flat 

 bands with the lateral edges folded in, so as to leave a broad furrow 

 in the middle. They consist of about six or seven rows of largo 

 angular cells, being finely ciliated on either side. The cellular 

 structure is perfectly different from that of the tentacles of the corals, 

 but remarkably resembling, for instance, that of the tentacles or 

 eye-pedicles of small G-astropoda (see pi. XII. fig. 1, 7c). ■ 



c. Groivth of the polyzoarium. 



The progressive growth of the polyzoarium of the present species 

 deserves a short notice, inasmuch as the observations on this point are 

 as yet rather imperfect. 



The terminal end of each fresh polyzoarium (see fig. la) is very thin 

 and membranaceous, being wholly composed of young cells, in different 

 stages of development. It is in all the incrusting species of this group of 

 Bryozoa free, becoming attached only in an advanced age. The first stage 

 (16) appears to be that of a small, flat and homogenous cell, filled with 

 a quantity of a dark granular substance. This cell is produced in the 

 form of a knosp from the previous cell of the same row. Young cells, 

 especially seem to have the power of propagating themselves by buds, 

 but in the old cells this mode is replaced by the formation of stato- 

 blasts. 



