woodward: anatomy of adeoeeis. 143 



structure he completely overlooked, whence his representation of the 

 posterior border of this tooth as divided into five processes. 



The most striking point of comparison between the radula of Rissoia 

 and that of Adeorlis thus becomes one of dissimilarity, so that Adeorhis 

 appears to stand alone in possessing the cleft base to the central 

 tooth. Nevertheless, when we compare the whole radula of these 

 two forms, we find that the general facies of the two are distinctly 

 similar ; this is especially noticeable in the character of the admedians 

 and the laterals in the two forms (see PI. VIII, Pigs. 3 and 4). The 

 admedians have in both genera somewhat long bases, and well-marked 

 denticulate free margins, provided with one large cusp, on either side 

 of which are a number of smaller ones. The laterals when turned 

 outwards are seen to be flattened with a distal expansion terminating 

 in a denticulate margin. On the whole, setting on one side the basal 

 denticle of the central tooth in Rissoia and the lobed character of 

 the base of the same tooth in Adeorhis, I find that the radula of the 

 latter more nearly approximates to that of the former than it does 

 to that of any other Teenioglossate genus with which I am familiar. 



A short, narrow oesophagus (PI. VIII, Fig. 5, ces.) leads from the 

 buccal mass, but soon enlarges into a complicated glandular body 

 (o.g.), where the lumen of the oesophagus becomes split up by a series 

 of infoldings of the wall into what appear in section to be several 

 distinct tubes uniting both anteriorly and posteriorly ; the whole 

 forms a glandular tubular organ and appears to be comparable to 

 the " Vorderdarmdriise " which Haller [8] has described in Natica 

 lineata and in Sigaretus. A pair of small salivary tubes {s.g.) are 

 situated just in front of this organ. From the latter a long tube 

 {ces.) runs back to the stomach {st.), which is of considerable size and 

 divided by two constrictions into three chanabers ; into the posterior 

 of these open the oesophagus and the bile duct (b.d.). The intestine 

 {int.) arises from the middle chamber, while the anterior chamber 

 is a blind diverticulum {cr.s.), having all the relations of a crystalline 

 style sac, and not unlike that described by Moore [9] in TypJiolia 

 and other forms. The intestine forms one or two loops in the substance 

 of the liver, and finally crosses over to the right side opening near the 

 anterior margin of the mantle. 



Genital Organs. — Of the two specimens examined, one was a male 

 and the other a female. The male possesses no penis, nor any 

 accessory glands. The testis occupies the dorsal border of the visceral 

 mass; it is a tubular gland communicating with the mantle cavity 

 by a vas deferens, which opens high up and close to the external 

 orifice of the kidney. 



The female genital organs consist of an ovary, containing large 

 ova, situated behind and above the stomach ; a short, narrow duct 

 originates from this and soon passes into a large glandular tube, which 

 after running parallel to the rectum for a short distance opens into 

 the mantle cavity. 



The excretory organ is of fair size, and opens directly into the 

 mantle cavity near its posterior limit, without the intervention of 

 a long ureter. 



VOL. III. — DECEMBER, 1898. 10 



