112 Mr. R. T. Lowe on new Maderan Land Shells. 



Lastly, we must know the spawn and brood of those kinds of 

 Natica or other moUusks!^ (Archiv, p. 29.). 



" I do not give up the hope, that we may yet determine at 

 least the genus of this mollusk ; and I found this hope mainly 

 upon the very characteristic form of the spermatozoa, in addition 

 to the other features enumerated. 



" It is very interesting, that from the form of the spermatozoa, 

 our mollusk can hardly belong to either the Nudibranchiata or 

 the Tectibranchiata, whose linear spermatozoa have been made 

 perfectly well-known by KoUiker. This is so much the more 

 worthy of notice, since it is in harmony with the indications 

 afforded by the shell and by the general structure of the young 

 mollusk, from which the animal would be referred to the Pectini- 

 branchiata. 



'' Among these, the peculiar form both of the shell and of the 

 spermatozoa excludes the Canalifera from consideration. But 

 among the Trochoidse to which Natica belongs, cercariform or 

 knitting-needle-shaped spermatozoa occur among a few genera, 

 and were observed by Kolliker in Trochus cinerarius, L. Wagner, 

 Erdl, and Kolliker observed similar ones in Patella and Chiton. 

 Wagner and Erdl found them in Haliotis among the Scuti- 

 branchiata, and Siebold in Vermetus among the Tubulibranchiata. 

 The spermatozoa of Natica and its aUies are yet unknown. 



" In investigations with reference to this matter, it will be 

 especially important to recollect the terminal enlargement of the 

 spermatozoa, which up to this time has been observed in no 

 Gasteropod, but in the spermatozoa of our mollusk is never 

 wanting/' 



IX. — Brief Diagnostic Notices of new Madei^an Land Shells. 

 By R. T. Lowe, M.A. 



VlTllINA, D 



ap. 



1. ViTRiNA Behnii. — Prim, (in Trans. Cam. Phil. Soc. vol. iv. 

 Part 1), tab. 5. f. 1 b. V. Ruivensis, Couth. Pf. Mon. ii. 507. 

 Differt a V. Lamarckii, Per. (Prim. loc. cit. f. 1 a) testa haliotoi- 

 dea patula depressa, apertura auriformi ad apicem usque pervia, 

 anfractibus tantum duobus, spira laterali vix uUa, &c. ; necnon 

 animale. 



Speciem icone supra citata distinctam, et plures jam annos in 

 honorem cl. Professoris Kielensis dicatam stabilivi. 

 Hah. in Madera. 



Helix, L. 



§. Leptaxis, Lowe. 



2. Helix membranacea. — Ab H.furva, Lowe, juniore caute 



