820 PEOF. G. C. BOURNE ON THE [N"ov. 17, 



oiveni, and >Sej)taria [Navicella) janelli. The position and general 

 anatomy of the Ividney of Neritina Jhtviatilis had been previously 

 described by Landsberg (24) ; and Perrier adds some details 

 relating to the trabecular structure of the excretory portion of 

 the kidney and the reno-pericardial canal. He did not, however, 

 fully elucidate the relations of the glandular and non-glandular 

 parts of the kidney, and described the latter as a closed sac inter- 

 vening between the kidney and the pericardium. This error was 

 afterwards corrected by Lenssen. The most important part of 

 Perrier's work, in so far as it relates to the Neritidse, is his 

 account of the heart. He discovered and gave an accurate figure 

 of the left auricle and showed that, contrary to Landsberg's state- 

 ments, the ventricle is in fact traversed by the rectum. 



Bergh (2) in 1890, as an addendum to his paper on Titiscania, 

 gives an account of the anatomy of Nerita jjeloronta and Xeritella 

 {Neritina) pulligera. This is the first attempt, since Quoy and 

 Gaimard, to give a complete account of the anatomy of Nerita, 

 but it is unfortunately very incomplete and contains some 

 serious errors and omissions. For ex.ample, Bergh denies the 

 existence of a second auricle, and lays considerable stress on its 

 absence. He describes the eyes as open, whereas they are in fact 

 closed. His description of the nervous system, correct enough as 

 far as it goes, is no advance on the original description of Bouvier. 

 He gives a more or less detailed and tolerably correct account of 

 the buccal bulb, odontophore and radula, and notes the presence 

 of salivary glands, but mistakes an oesophageal dilatation for the 

 stomach, and describes the true stomach as enlargements of 

 the hepatic ducts. The position of pericardium and kidney are 

 correctly described withovit adding anything to previous know- 

 ledge of the subject ; but the reno-pericardial duct was not 

 recognized. All of Bergh's specimens appear to have been 

 females, and he makes an attempt to describe the complicated 

 accessory generative ducts and glands, but, as he says, " bei den 

 voi'liegenden Materiale konnten die ganz unklaren Verhaltnisse 

 dieser Theile nicht genauer eruirt werden." He recognized, how- 

 ever, the spermatophore-sac, and gives a good outline figvire of a 

 spermatophore of N. pulligera. 



In 1892 two short papers by Boutan (6) and Bouvier (10), the 

 atter published very shortly after the former, established the 

 existence of a supra-intestinal nerve in Nerita and Septaria, thus 

 restoring the Neritacea to their proper place among the Strepto- 

 neurous Rhipidoglossa. Shortly afterwards Boutan (7) published 

 a further account of the nervous system of Nerita p>olita and 

 Septaria {Navicella) porcellana, in which the course of the supra- 

 intestinal nerve is correctly figured, but he failed to recognize the 

 supra-intestinal ganglion which Bouvier had signalized in the 

 previous year. Boutan appears to have been in error as to the 

 position of the osphradium, which he says " s'etend le long du 

 septum branchial qui reunit la branchie au plancher de la cavite 

 et est a peine distinct a I'oeil nu." The osphradium, as I shall 



