NOTICES OF SERIALS, 
28 
Occurrence of Diodonta Fragilis at Weymouth, by W. Thompson : Description 
of a second species of the Genus Procnias, by P. L. Sclater, A.M. ; Description 
of some new species of Birds, by the Viscount Du Bus de Gisignies : Description of 
a new species of Petrogale, by Dr. J. E. Gray. Meteorological Observations and 
Table for September, 1855. 
No. 96. December.—(Charles C. Babington, A.M. F.R.S.) On the Batra- 
chian Ranunculi of Britain. (Thomas Williams, M.D., London, F.L.S.) On the 
mechanism of aquatic respiration, and on the structure of the organs of breathing in 
Invertebrate animals; with a plate. (Dr. J. E. Gray, F.R.S., &c.,) On the genera 
of mollusca, and on the genus assiminia in particular. (Thomas Davidson, F.G.S.) 
A few remarks on the Brachiopoda; with a plate. (William Clark) On the phe¬ 
nomena of the reproduction of the chitons. What form the young chiton might 
assume was always of great interest to the naturalist—did it pass from the ova into 
an intermediate larvar condition ; or had it always the true chiton form, even when 
immature? For want of knowledge on this subject the chitons have not only been 
tossed from class to class among the mollusca, but also from the order mollusca it¬ 
self, and were placed by Blainville among the Annellidan articulata. From all these 
facts, the importance of chronicling every investigation about these animals will be 
clearly seen. On the 23rd of last July, Mr. Clark placed several specimens of chiton 
cinereus in saucers filled with salt-water. On the day of capture one of the ani¬ 
mals discharged a quantity of ova, not in volleys but by one or two every second 
for at least fifteen minutes, forming a batch of 1,300 to 1,500, many more remaining 
in the ovaria ; they were of a pale yellow colour, but globular form, being a little 
compressed at their axes, and about 100th part of an inch in diameter ; they were 
attached by means of a viscid fluid. On the 24th July, they still remained inert at 
the bottom of the saucer. On the 25th, they had all become detached from their 
nidus, and swam with great vivacity through every part of the water, and crossing 
the large saucer in 30 or 40 seconds. As soon as the motion commenced the ova 
lost the sub-globular figure, and assumed that of a sub-elongated oval approaching 
the chiton shape. On the 30th, they had altogether cast off the embryonic cover¬ 
ing, and exhibited the complete form of the chiton, and at this period they appeared 
to lose their natatory powers. (C. C. Babington, M.D., F.R.S.) Note on Linaria 
sepium Allman. Bibliographical notices : Catalogue of the genera and sub-genera 
of birds in the British Museum : Descriptive and illustrated catalogue of the His¬ 
tological series contained in the Museum of the Royal College of Surgeons. Vol. 
II.—Proceedings of Learned Societies: Zoological Society, July 25, 1854. Mis¬ 
cellaneous—On the Shropshire mollusca, by J. Gwyn Jeffreys: On the arrested 
development of the Tadpole of the common Frog, by W. Davies: List of species 
of mollusca obtained by Professor Goodsir, from Spitzbergen, by Mr. R. Andrew. 
Meteorological observations and table for October, 1855. Title page to Volume 
XVI. 
Quarterly Journal of Microscopical Science. No. 13, October, 1855. 
8vo. Price 4s. With Woodcuts and Lithographic Illustrations, London, S. 
Highley, 32, Fleet-street. 
(W. Gregory, M.D., F.R.S.E.) Notice of some new species of British freshwater 
Diatomaceas. "(G. Busk, F.R.S.) An account of the structure and relations of 
Sagitta Bipunctata. This little animal, which has the form of a pointed needle, is 
from one to two inches in length, and is as transparent as the clearest glass, in warm 
calm weather, it swims on the surface of the sea, and occasionally in the most sur¬ 
prising numbers ; at such times it may be procured without difficulty, by means of a 
small towing net over the side of the boat. Its minute size, and the extreme delicacy 
and transparency of its tissues, make it peculiarly an object of microscopical inves¬ 
tigation. In our latitudes it appears to be in a state of the most complete maturity 
in August and September. With respect to its systematic position, authors are 
still very much in doubt. Mr. Huxley places it among the annulose animals; but 
says that the study of its development can alone decide to which sub division of 
the Annulose kingdom Sagitta belongs. (John Gorham, M.R.C.S.E.) On the 
