INVERTEBRATA, ORYPTOGAMIA, MICROSCOPY, ETC. 55 



Viviparity of Helix Studeriana.* — Tliree species of Helix have 

 already been sliowu to bo viviparous — Helix {Partula) gibba, H. 

 rupestris, and H. inceqiialis. To these a fourth is now added, M. C. 

 Viguier having examined the portions of two specimens (in alcohol) 

 of H. Studeriana (Ferussac) brought from the Seychelles in 1875 by 

 the naturalist of one of the ' Venus ' expeditions. 



The first specimen consisted of the uterus only. It was of a dull 

 white colour, and perfectly opaque. When opened, it was found 

 that its walls were excessively thin and transparent ; but it was 

 filled with a white, granular substance, which, falling to the bottom 

 of the vessel, allowed two membranous sacs to be seen, which were 

 filled with the same white substance, and each contained a young 

 Helix. The animals measured "009 to '01 mm. in diameter, and 

 had a spire of nearly two whorls. In the centre of the foot was 

 a kind of cord spirally twisted and formed by the rolliug up of 

 the membrane of the sac. It was ascertained to be continuous with 

 the internal organs, which, however, it was impossible to make out, 

 having regard to the condition of the specimens. The same granular, 

 white substance, probably a nutritive vitellus, filled the interior of 

 this cord, which was not traversed by any vessels. 



It is not suggested that there is here a case of true placentation, 

 as has been observed in the Saljxe. The young animal is suspended 

 by its cord in the interior of the sac, which is simply contiguous to 

 and not continuous with the walls of the uterus. 



The second specimen consisted of the uterus and its attendant 

 organs. In this case the walls were transparent, and two young 

 animals ('014 to "OlS mm. in diameter) could be seen through them, 

 with only scattered clots of white substance, the animals being more 

 fully developed than in the first specimen. 



The necessity of preserving the specimens, which are unique, 

 prevented any closer examination. 



Organs of Taste in Heteropoda.t — F. Todaro and C. Milone 

 found in sections prepared from the so-called " proboscis " of 

 Pterotrachea, preserved in Owen's fluid, a special epithelial pro- 

 tuberance in the form of a bulb or knob, which they consider the 

 gustatory organ. This was first found in the epithelium of the 

 mucous membrane of the mouth, and afterwards in the external 

 epithelium of the anterior extremity of the " proboscis " surrounding 

 the oral aperture. 



Tiio gustatory papillaj were found in very long, cylindrical 

 epithelium-cells of the proboscis ; this stratum of cells is covered by a 

 thick cuticular layer on which arise towards the bottom of the cavity 

 the cuticular teeth and the radula. In the mouth itself the cylindrical 

 epithelimn is jdaced in the connective fibrillar tissue of the mucosa. 

 The gustatory papillaa of the oral mucosa arc found disposed in series 

 (two or three series on each side) along the lateral wall, extending 

 from the base of the cavity, i. c. in front of the radula, to the labial 

 margin, and continue spread irregularly in the external skin. 



* 'ComptcH Reiiflu.s,' Ixxxix. (1879) p. SGC. 



t 'Trans. R. Actiul. doi I,incei,' iii. (1870) p. 2^)1. 



