Miscellaneous. 449 



operated upon to take air at the surface of the water, they neither 

 presented in their movements nor in their mode of life any apparent 

 modification, the cutaneous respiration replacing the branchial. — 

 Comptes Rendus, August 5, 1867, pp. 242-246. 



Note on my former Communication on a supposed New Species of 

 Planarian Worm. 



To the Editors of the Annals and Magazine of Natural History. 



Gentlemen, — In the October Number of the ' Annals ' I drew your 

 attention to what I believed to be an undescribed species of a Rhab- 

 doccel Planarian worm, which 1 proj)osed to call TypMoplana nigra. 

 Living as I do in the country, I am in a great measure dependent on 

 my own library for books of reference. Since writing to you, I have 

 procured a copy of Oscar Schmidt's work ' Die Rhabdocoelen Stru- 

 delwiirmer,' and on Taf. 4. fig. 10 I find an excellent figure of my 

 Planaria, which appears to be not a Typhloplana, but a Mesostomum, 

 and the M. persoiiatum discovered by Schmidt. From what Dr. 

 Schmidt says, it appears that the adult animal is possessed of eyes, 

 which, however, are concealed in the black pigment ; young indivi- 

 duals just emerging from the egg have two distinct eye-specks. The 

 chief difference between the genera Mesostomum and Typhloplana is 

 the absence of eyes in the latter. Hence, as I could discover none 

 in the specimens I examined, I referred the creature to the genus 

 Typhloplana. It is, however, clearly identical with the Mesostomum 

 personatum of Schuiidt, and I cancel my former conjecture, and add 

 this species of Rhabdocoel planaria to the British fauna. Hab. Reedy 

 pond near Preston. 



I remain. Gentlemen, 



Yours sincerely, 

 Preston Rectory, Wellington, Salop. W. Houghton. 



Nov. 15, 1867. 



On the Development o/Sepiola. By E. Mecznikow. 

 (Notice by E. Claparede.) 



As M. Mecznikow's memoir is published in Russian, we give a 

 rather detailed notice of it. 



Besides the old writings of Bohadsch and Delle Chiaje, we possess 

 on the development of the Cephalopoda an unsatisfactory memoir by 

 M. Van Beneden, and a more important work by M. Kolliker. The 

 latter, although more complete, still leaves some gaps to be filled up. 



The ova of the Sepiol<s, investigated at Naples by the author, 

 resemble the eggs of the common fowl in their form, although not 

 in their size (they are only 4 millims. in length) ; they are con- 

 tained to the number of fifteen together in a colourless mucilage. 

 Each ovum is furnished only with a single envelope ; this chorion 

 does not appear to correspond with the outer membrane of the ova 

 with double envelopes of other Cephalopoda (Sepice, Squids), but 

 rather to their inner envelope, which M. Kolliker and others have 

 regarded as the vitelline membrane. This latter denomination seems 



