1869.] and Membranipora Bengalensis. 41 



three alternate primaries, subsequently and gradually on all six. 

 In very old specimens, the tips of the next, and even partially of the 

 third series, become white. Wherever there is a large accumulation of 

 cnidce on the column, or where the cnidce are of a larger size, the 

 white specks in the integument are readily recognised, even with the 

 naked eye. 



To return to our former statement regarding the position of 

 the tentacles ; the next, or second series of them, consists of twelve,* 

 being distinctly traceable by a bipavtition of the primary tentacles, 

 with which they are connected on one side, while on the other, they 

 extend to the lip. Thus, in position, the secondary tentacles origin- 

 ate more peripherally, and in pairs alternate with the primary ones ; 

 they often are the longest of all, being in large specimens about If — 2 

 inches in length, and most of them indicate by their whitish tips the 

 presence of numerous cnidcs. This statement, relative to the position 

 of the two first series of tentacles, is in the present species, based upon 

 direct observation, but it was impossible to do the same with the 

 other series ; though in the next at least, or the third cicle, a more or 

 less regular bi-division partially appeared observable. Sometimes I 

 could notice three tentacles of a next series springing up from one of 

 the former series ; but this certainly is not the rule. Moreover, judg- 

 ing from the total number of the tentacles, which appears to be rather 

 constant in specimens of equal size, and allowing for accidental ir- 

 regularities, we cannot be far from the truth, when we also accept a 

 regular bipartition for the third and fourth series, as partially 

 represented in fig. 2 of pi. XL By this bi-division we obtain very 

 closely the total number observed in live specimens, being about 160. 

 In the specimen figured on pi. X, the tentacles of the first series had 

 a length of \\ inches, those of the second If, of the third 1J, of the 

 fourth f, and of the fifth \ of an inch. 



f. The mouth is a transversally oval, or more or less linear opening, 

 surrounded by prominent lips, which consist of twelve, elongated, 

 inflated tubercles, between each pair of which originates one primary 

 tentacle. On the two opposite ends of the longitudinal axis, ter- 

 minate the gonidial canals with small roundish openings, (see c 



* The second series of the septa is only six, like the first ; thus tentacles and 

 septa do not, as already stated, take equal steps in their development. 



