Observations on British Zoophytes. 317 
inches and a half. The number of lips of the latter was 
about fort}^ the radiating canals, each having a long ovisac; 
about eighty, and the marginal tentacles, by estimation, 
four hundred. On examining the ovaries, I found that the 
eggs were hatched, and the young, in the form of almost 
invisible planulge, were issuing from the ovisacs. These 
were gently extracted with a glass syringe, an instrument 
so useful to those who practise the obstetric art amongst the 
hydroidse, and were placed about three weeks ago in glass 
tanks of clean sea-water prepared for their reception. Many 
thousands of larvse were placed in the tanks, and of those, 
about a score have been developed into Campanularian 
polyps ; about a hundred are still progressing to that end, 
and the rest have disappeared. It was with no little 
impatience and anxiety that I saw the Planula during a 
fortnight fix itself to the glass, spread itself out into a short 
thread, secrete its scleroderm, put forth its polyp-bud— this 
last slowly swelling day by day, until at last it opened, 
and a polyp appeared, furnished with twelve alternating 
tentacles, joined together for about one-third of their length 
by a web, the polyp enclosed in a cell terminating in many 
acuminate segments. It is now about six years ago that I 
was watching, in like manner, the slow evolution of a bud 
from a Campanularian Zoophyte, the Laomedea acuminata 
of Alder — the Campanulina of Van Beneden — the bud 
opened, and a bright green medusoid issued forth, having 
four lips and two tentacles. The polyp form of ^quoria 
vitrina is, as far as I can determine, identical with that of 
L. acuminata in shape ; but is so excessively small — quite 
invisible to the naked eye — that we must wait for further 
development before we can determine their identity. Ge- 
ganbaur has proved that the Medusoid of Yelella acquires a 
further number of canals and tentacles ; and I have else- 
where recorded the successive changes which occur in the 
Medusoids of several species of Atractylis. It is also certain 
that such increase in the number of elements does occur in 
^quoria vitrina, for the smaller specimens have always a 
less number than the larger. Meantime, the question as to 
the larval state of JEquoria vitrina is settled. This, the 
