pote 
II. On the Nervous System of Beroé Pileus, Lam., and on the Structure of its Cilia. By 
Roserr E. Grant, M.D., F.R.S. Ed., L.S., G.S., Z.8., &c., Professor of Comparative 
Anatomy and Zoology in the University of London. 
Communicated January 8, 1833. 
IN the month of September last I obtained on the coast of Sheppey, in the Thames, a 
specimen of the globular Beroé, Beroé Pileus, Lam., a species which has been observed 
occasionally on the coasts of England and Scotland, and which I had once before met 
with on the coast of Staffa. It constitutes the genus Pleurobrachia of Dr. Fleming, 
and the Eucharis of Péron and M. Blainville. I found this little animal floating with 
myriads of minute Equoree and other Medusaria in the harbour of Sheerness. The 
boatmen, who seemed to be familiar with it under the name of the spawn of the Sea- 
egg (Echinus), which it somewhat resembles in its globular and ribbed form, assured 
me that often in hot and calm weather they swarm, with the little Meduse, in such 
numbers as to cover the surface of the water in all this part of the estuary of the Thames. 
The animal has a regular oval form, with its longest diameter, from the mouth to the 
anus, about six lines, and its breadth about four lines. The general texture of the body 
is quite transparent and colourless. The eight equidistant bands which support the 
cilia, extend along the surface from the margins of the mouth to the anus, and appear 
more firm in their texture and less transparent, than the rest of the body. There are 
four prominent membranous lobes placed around the mouth, which the animal can 
retract at pleasure. The mouth and esophagus are wide; and the latter continues so 
to the stomach, which extends to the centre of the body. The intestine continues 
straight, equal, and narrow, from the stomach to the anus, which has a prominent cir- 
cular margin. The digestive organs contained no perceptible food, but Fabricius has 
often observed minute Crustacea in that cavity. The ovaries consisted of two lengthened 
clusters of small spherical gemmules, of a lively crimson-red colour, extending along 
the sides of the intestine and stomach. Their bright red colour contrasted beautifully 
with the glassy transparency of the general texture of the animal ; and I have generally 
observed that the lively hues presented by the Acalepha, depend on the bright opaque 
colours of their reproductive gemmules, which are often red, sometimes yellow, or 
brown, or purple. The two tentacula are remarkable in this species of Beroé for their 
complex structure, and their peculiar movements. They extend from two curved tubes 
placed near the sides of the stomach, which pass obliquely downwards and outwards to 
terminate between two of the bands at some distance above the mouth. They are about 
four times the length of the animal, and consist of two thin white filaments, round, and 
VOL. I. c 
