818 PROF. G. C. BOURXE ON THE [NoV. 17, 



Cet organe est creux et contient dans sa cavite, accolles les nns aux 

 auti'es, plusieui's corps en massue allongee, fiuissant en filaments, 

 lis sont resistants, comme fibreux, et paraissent grenus a la 

 loupe. Nous ne pouvons deviner I'usage de ce petit appai-eil, qui 

 remplit sans doute quelques fonctions relatives a la geneiation, 

 23uisqu'on ne le trouve que cliez les femelles. Plus en dehors est 

 I'uterus, compose d'une poclie pyriforme et d'un renflement qui 

 lui est accoUe, lequel contenait une grande quantited'oeufs, ronds 

 blancs et cretaces. L'oviducte, gios long et tortueux, fait com- 

 muniquer cet organe avec I'ovaire, place an bord droit du foie." 

 Though this descrijjtion and the figure accomiDanying it are 

 inexact, it is evident that the " corps pyriforme " is the sperma- 

 tophore-sac, the " corps en massue allongee " are the sperma- 

 tophores, the " glande sti'iee en tiavers" is the ootype, with its 

 glandular walls, the "uterus," as described and figured by these 

 authors, has no separate existence, but the " rentiement qui lui 

 est accolle " is the crystal-sac, which does, in fact, open into the 

 distal end of the ootype. It also seems pi-obable that MM. Quoy 

 and Gaimard mistook the spherical crystalline concretions in the 

 crystal-sac for ova. 



Of the male, Quoy and Gaimard give a very insufficient account 

 of the accessory generative organs, but observed the excessively 

 long coiled region of the sperm-duct to which I have given the 

 name of epididymis. 



In an earlier memoir Quoy and Gaimard (35) gave a super- 

 ficial account of the structure of Nerita, which only merits 

 attention because it contains two figures showing the modification 

 of the cephalic integument at the base and to the inside of the 

 right tentacle of the inale, which has been referred to, but 

 seldom correctly figured or described, by subsequent authors as 

 a " cephalic penis." In the figures referred to this structure 

 is represented in the correct position, but simply as a conical 

 eminence, without any detail. 



From the time of Quoy and Gaimard there is no work dealing 

 with the anatomy of Neriia till that of Bouvier in 1886. Yon 

 Jhering (22), in his well-known work on the nervous system of 

 mollusca, abruptly removes the whole of the ISTeiitacea from their 

 position alongside of the other Ehipidoglossa and places them in 

 a class Orthoneura, which has long since been broken up, its 

 contents being restored to their proper places by subsequent and 

 more exact observers. But his investigations were confined to 

 the nervous system of Xeritina fluviatills, and had he carefully 

 studied the anatomy of some of the larger species of Nerita or 

 of a Septaria he would probably have paused before pi-omulgating 

 the opinions set forth in his lengthy memoir. 



Bouvier (8), in a preliminary note published in 1886, gave a 

 short account of the principal external features of the anatomy 

 of Nerita and some details of the nervous system, but the reader 

 should turn for a more complete account to his great Avork (9) 

 on the nervous system of proso branchiate Gasti'opods. As he 



