QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 417 



consistent mode of origin, if it really is so. He objects to 

 Kiipflfer's observations on the matter, as not furnishing data 

 for comparison, since he worked upon Phallusia canina, the 

 ova and embryo of which are not so transparent as those of 

 Ph. mamm'dlaris. He maintains that this species must be 

 used for the observation ofAscidian development, or one equally 

 transparent. Ganin and Donitz he very wisely admonishes 

 to study suitable material before critcising Kowalewsky's 

 statements. Metschnikoff writes from Funchal, in Madeira. 



A very excellent and full account (illustrated by three 

 plates) of Kowalewsky's, Kiipffer's, and other researches 

 on the development of the Ascidians, is given by M. Girard, 

 in the second part of Prof. Lacaze Duthiers' new ' Archives 

 de Zoologie.' We recommend this to readers. 



The Otocysts or Auditory Capsules of the Mollusca (Gaster- 

 opoda), by Prof. Henry de Lacaze Duthiers. — The first and 

 second parts of his ' Archives de Zoologie ' contain this 

 elaborate and beautifully illustrated memoir by the illustrious 

 French zoologist. Its publication was delayed, together with 

 the whole Archiv, during the war, hence it is only now that 

 the author submits the details and drawings establishing the 

 fact which he announced as long ago as 1868, and which we 

 noticed at that time. In the interval Lacaze Duthiers' re- 

 searches have been confirmed by Leydig, who has published 

 on the subject in ' Schultze's Archiv' (see this Journal for 

 1871, p. 421). We need hardly remind the reader that what 

 Prof. Lacaze Duthiers then announced Avas, that the otolithic 

 capsules of Gasteropodous molluscs (for which he now pro- 

 poses the convenient designation of otocysts) do not receive 

 their nerve from the pedal ganglion, as commonly supposed 

 by such men as himself, Leydig, Huxley, and others, but that 

 the auditory nerve descends to the otocyst from the cephalic 

 ganglion. Thus, as in Lleteropods and Nudibranchs, the 

 cephalic ganglion is the centre of the sensory organs. In the 

 present memoir the fullest details are given as to a variety of 

 genera of Gasteropods — Cyclostoma, Pileopsis, Paludina, 

 Ancylus, Neritina, Helix, Planorbis, Limax, Patella, &c. 

 More than thirty species have been studied. Where the 

 object of a memoir is to bring forward evidence to establish 

 a ^proposition of a startling character, it is useless to give 

 any abstracts of the statements it contains. Comparative 

 anatomists must examine the beautiful drawings of M. 

 Lacaze Duthiers for themselves. We may just observe that 

 the evidence admits of no kind of doubt, and all that has 

 been said about the connection of the pedal ganglion 

 and auditory function is simply exploded. We have 



A'OL. XII. — NEW SER. G G 



