MOLLUSCA. 419 



The British Fauna has also received additions from E. 

 Forbes, who has described and figured some animals found 

 by M' Andrew. (Annals, xiv, p. 410.) Of Mollusca we 

 have the following : Emaryinula crassa, Sow., previously 

 known only as fossil; Eiilima Mac Andrei, new species (vid. 

 infra) ; Pleurotoma teres, Forbes, figured in Reeves' s Conch, 

 iconic, pi. 19, f. 161 ; a variety of Natica monilifera, Chem- 

 nitzia fulvo-cincta (Turritella sp.), Thompson ; Pleu- 

 rotoma Bothii, Smith ; Cyprina trianyularis, Mont. ; Pecten 

 Landsburgi. 



Heinrich Meckel has published in Miiller's Archiv f. 

 Anatomic, &c. (1814, p. 483) his researches on the sexual 

 organs of the Hermaphrodite Molluscs, and illustrated them 

 with two plates of very clear figures. This memoir is of 

 extreme importance as regards the significance of the 

 organs, about which so much has already been written. 

 The author regards the organ, which is situated in the liver, 

 neither as a testis nor ovary, but, as Siebold has latterly 

 done, as both together ; showing that the individual sacculi, 

 of which the organ is composed, are formed of two sacculi 

 one within the other, of which the internal contains sper- 

 matozoa, and the external ova. From this androgynous 

 gland proceed two canals, also contained the one within the 

 other, which thus reach the glandula uterina, the testis of 

 Cuvier, in which, according to the author, the albumen is 

 formed. From this point the two canals proceed in union, 

 and indeed connected with each other by a groove through- 

 out their whole length, as far as the vulva. 



The so-called pedunculate vesicle is regarded by Meckel 

 as a vesicula seminalis, which, at the time of copulation 

 receives the semen; the " organes multifides" he looks upon 

 as mucous organs. The sexual organs of Helix pomatia, 

 and what is of especial interest, those of Thetis, Doris, Tri- 

 tonia, and Pleurobranchaea are figured ; and they correspond 

 in this respect with Helix, that the vas deferens, before 

 entering the vulva, diverges in order to reach the penis ; 

 and, lastly, those of Aplysia, Bulltea, Doridium, Umbrella, 



