272 QUARTERLY CHRONICLE. 
Details are given respecting the development of—(1) the 
Cartilage ; (2) the Tegmentum ; (3) the Membrana basilaris, 
upon which the author lays great stress; (4) of the ner- 
vous elements. Parts whose development still requires fur- 
ther investigation are—(1) ‘The Tigmental cells; (2) those 
of the triangular cartilage ; (3) of the denticulate cells; (4) 
of the Papilla spiralis. 
The second paper is chiefly devoted to an account of the 
minute structure of the Cochlear ganglion and the terminal 
filaments of the Acoustic nerve. 
3. “ On some Tropical Larval Forms,” by Dr. C. Sem- 
per, of Wurzburg.—Shortly before the Author’s departure 
for the Philippine Islands in the year 1858, his attention 
was directed by Prof. Behn, of Kiel, to a minute marine 
animal which that observer had met with in his voyage round 
the world in very various regions of the tropical seas. ‘This 
was acylindrical creature about 6mm long, and characterised 
by a longitudinal tract of cilia running from one end to the 
other. 
Dr. Semper noticed this apparently larval form for the 
first time somewhere about 42° S.L. near the Cape, as the 
ship was passing through a broad shoal as it were, of the 
most various kinds of oceanic creatures, brought by the warm 
Mozambique current flowing out of the Indian Ocean. The 
next occasion upon which he fell in with it was in the Straits 
of Sunda and on the South Coast of Java. 
The body presents the form of a cylindrical sac open at 
each end, and having thick walls whose colour gives the 
creature a beautiful striped or banded aspect. The oral 
opening, which is always in front when: the animal swims, 
leads into a short sort of infundibuliform pharynx, from the 
lower end of which six wide mesenteric bands proceed 
through the ciliated abdominal cavity to the posterior end of 
the body. The anal orifice is of the same size as the oral. -The 
integument contains very numerous nematocysts of two kinds, 
one of an elongated oval form, and the other of slender clavate 
shape. The ciliated band, consisting of closely approximated 
cirrhi, can be reclined to either side, but in the active state 
stands erect. It is situated along the middle of a yellowish- 
brown flattened elevation of corresponding length. 
From the above particulars the author concluded, without 
doubt, that the creature must be the larva of an Actinia. 
But at the same time he met with another smaller larva, 
which, instead of a ciliated longitudinal band, was furnished 
with a circlet of cilia like that of au Annelid larva. He made no 
notes respecting the conformation of its stomach or ventral 
