ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 587 



appears to have escaped previous observers. The pouch is enormously 

 developecl during the reproductive period ; the central mass is 

 pyriform in shape, and gives off two flattened prolongations ; the 

 angle between these is covered by a silvery elastic membrane, and 

 contains an ovoid yellowish gland ; the investing layer contains small 

 cylindi'ical cells and others which are fouj.' times as large, are 

 spherical in form, and are derived from the former. In Odo'pus 

 vulgaris the anterior part of the wall is largely adherent to the wall 

 of the bladder, and the free part only forms a diaphragm, in the centre 

 of which is the orifice for the ink ; no silvery elastic layer could be 

 detected in this species. The author promises to give figures in 

 illustration of his results. 



Regeneration of Lost Parts in the Squid.* — Prof. A. E. Verrill 



has observed numerous instances in Loligo Pealei and Ommastrephes 

 illecebrosus of torn-off suckers having been reproduced, as well as of 

 the reproduction of entire tentacular arms. These regenerated parts 

 are mostly of smaller size, and the author suggests that it is probable 

 that some of the normal European species of Loligo that have been 

 based on the smaller size of the tentacular arms or of the suckers are 

 due to similar cases of regeneration. 



S. Eichiardi has also published f a note on two cases of the 

 reproduction of the arms of Octopus vulgaris. 



Enemies of Ostreiculture,^ — M. A. Giard discusses certain 

 animals which are, or are supposed to be, inimical to oysters. He 

 defends the species of Pohjnoe from the charges that have been 

 brought against them, and states that they only live among and not 

 on these molluscs. The most terrible enemy is the sponge Cliona 

 celata, which destroys the shell by boring. A small Annelid of an 

 unnamed species of the genus Leucodora is also partly to blame ; the 

 author calls it L. sanguinea. In these cases there appears to be a 

 kind of chalk-" hunger," and the same cause is used as an explanation 

 of the eroded character of the shells of Lymnceus and Helix in certain 

 localities or in captivity ; and it may be that the same form of want 

 will explain the perforating habits of the Echinid Strong ijlocentrotus 

 lividus. 



MoUusca of the Gulf of Mexico.§— Mr. W. H. Dall has made a 

 preliminary examination of the results of the ' Blake ' dredgings in 

 the Gulf of Mexico in 1877-8, and gives the following as the most 

 interesting and important deductions which seem to result from the 

 facts before him. The collection contained about 500 species, or 

 excluding Pteropods and some other groups, 462 which are considered 

 in the paper. 



(1) The facts already known, that certain species of molluscs 

 have a very limited vertical range, forming respectively a littoral 

 and an abyssal fauna, are supplemented by the additional hitherto 



* Amer. Journ. Sci., xxi. (1881) pp. 333-4. 

 t Atti Soc. Tosc. Sci. Nat. (1881) pp. 248-9. 

 X Bull. Sci. Dap. Nord, iv. (1881) pp. 70-3. 

 § Bull. Mus. Cornp. Zool. Camb., vi. (1S80) p. 85. 



