496 Mr. A. W. Waters on a Structure in 



the ovicelligerous zooecia have a different shaped aperture, 

 larger than tliat of the ordinary zooecia, but more work is 

 required on the internal anatomy of these. Tlie limits of 

 the group Adeonidjo will have to be based partly upon tlie 

 form of the embryo. 



Tiie bodies described in this paper occur in Adeonella 

 lichenoides, A. poIystoweUa, Jj., A. jf'^ly^^orpha, B., A.con- 

 torta, Mich. ; but none were found in s})ecimens of A. plutatea, 

 B., Adeonellopsis distoma, B., in the new Adeonellopsis 

 referred to, or in Adeona foliacea, var./ascialis, Kirch. : that 

 is, we have it in several Adeonellie, but not as yet in 

 Adeo7ieUopsis. 



Now w'ith regard to tlie cliaracters of the Adeonidse, tlie 

 pigment is common to IloJoporellaj and we must emphasize 

 the fact that it is not the pigmentation of an external mem- 

 brane, but of the contents of the pore-tubes and pigment-cells 

 over the surface ; the long tubular pores occur in Mipiozoum, 

 Ilasivellia, &c. The long narrow avicularium without any 

 bar is a character of considerable importance ; but we also 

 find avicularia w ithout any bar in some Memhraniporce^ &c., 

 and the projecting process to which Busk refeis is well marked 

 thronghout the group, but as it occurs in Crihilina, Micro- 

 porella, a large number of Memhraniporce^ and other genera, 

 this character may be dismissed as of very secondary im- 

 portance. And with rt-gard to the occlusor muscle being 

 single, as stated by Busk, this is the rule with triangular 

 mandibles, whereas the semicircular ones have two bands, so 

 this is a useless character ; but although none of the characters 

 given by Busk can stand as he stated them, yet apparently 

 he was right in appreciating that there was the group 

 Adeonidse. 



All the ovaria of Adeonida^ seen, excepting Adeona 

 fvliacea, var. fuficialis, consist of two ovarian cells or 

 occasionally three, and with the exception mentioned, no 

 large ovarian cell has been met with. The ovaria originate 

 near the distal end, although close to the proximal end of 

 large embryos one or even three small ovarian cells sometimes 

 occur. In A. foliacea, var. fascialis, K., the ovaria at first 

 consist of two rather small ovarian cells, but later on one 

 may attain a model ate size. 



In the Bryozoa there are sometimes ovaria with only two, 

 or perhaps three, small ovarian cells, neitlier of which grows 

 to any large size, but passes into tlieovicell quite small. In 

 opposition to tiiis there are ovaria with man}' ovarian cells, 

 one or more of which often attain to a considerable size. 



