90 General Notes. J anuary, . 
pierced by pores, and the endoderm is formed by the immig | 
tion, one by one, of the blastodermic cells, this immigration” 
taking place only at the posterior part of the larva. In further” 
development the ectoderm appears to be double, but this appear | 
ance is due to a differentiation in the protoplasm of the cells; and 
glands, disposed in the ectoderm. The medusa does not neces 
sarily die after it has laid its eggs. Under favorable conditions it | 
lives, but changes in form, the umbrella relaxes, turns Upwat® gi 
and ultimately forms a sac having a few tentacles around its naf 
row opening. Meanwhile the pendant manubrium loses its tet: | 
tacles, and forms the base of the hydra-like animal, while the : 
mouth narrows to a pore, by means of which the animal fixes | 
itself. The cavities of the manubrium and of the larger $4 | 
formed from the reversed umbrella ultimately communicate, O 
ectodermic cells lining the latter each acquire a vibratile cilium | 
and become endodermic, and the upper opening does duty forse 
mouth. Dr. Otto Hamann (Fen. Zeitschrift fur cvissenschafin | 
1882) gives the results of his researches into the structure the 
tion. Mr. R. E. C. Stearns describes a new Pennatu 
Japan under the name of Radicipes pleurocristatus (Proc. ©" 
Nat. Mus., 1883, p. 96). This species has a furcate basa! “io 
well adapted for fixation in a muddy bottom. Mr. Stearns yee 
brings together numerous accounts tending to prove that eee 
tulids with simple axial rods have considerable swimming pe ogy 
——<A recent memoir of the Museum of Comparative Zoolos! 
is devoted to the Porpitidz and Velellidæ. Professor Aga 
