344 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



from that point to the posterior margin. Such a plication exists in 

 the specimen from Koumania, and, though somewhat obscure, it 

 appears to have been a kind of narrow tube-like process leading from 

 the apical region to the [absent] posterior border, and which internally 

 would have corresponded with a longitudinal groove. The apex of 

 this specimen is also wanting, its immediate area being obtuse or 

 rounded. 



The few species comprised in this genus certainly require some 

 revision, if only suitable material were available for examination, from 

 the fact that Reuss appears to have misinterpreted Rousseau's original 

 type of V. anmdata, which showed an external sculpturing of an 

 Inoceramoid type, as well as a cancellated structure. The V. anrmlata 

 of Reuss referred to a shell much more orbicular in contour, having 

 a greater number of concentric ridges and grooves, and therefore closer 

 together, and without evidence of surface cancellation. Judging from 

 the figures, it would appear that Reuss' shell is not a great way 

 removed from V. Pauli of Rudolf Hoernes, found in the Pontian beds 

 of Croatia, and possibly the present form might be united to both, but, 

 in the absence of better specimens for study, it is provisionally regarded 

 as a new species under the name of V. Roumaniensis. Rousseau 

 originally pointed out that this Pulmonate genus showed resemblances 

 to Ancylus and Siphonaria, whilst Fischer in his "Manuel" (p. 502) 

 has doubtfully placed it in the family Otinidae and close to Benson's 

 Camptonyx. In the case of Camptonyx, which is an Indian terrestrial 

 shell, there are some features in common with Valenciennesia, viz., 

 its pileiform shape, regular nigose surface, and the presence of an 

 external swollen rib to the right of the summit ; it differs, however, 

 in possessing a sub-spiral instead of non-spiral apex, besides being of 

 extremely small size, measuring only about 10 mm. in height. Ancylus, 

 again, although of fresh-water habit, is of patelliform shape, with 

 a spiral summit, and covered with fine and delicate radial markings ; 

 whilst Siphonaria is a marine genus, dilfering by being patelliform 

 and showing sculpture with radiating costae, but bearing a pi'ominent 

 external rib on the right margin. 



In further comparison the following remarks by Benson, made at 

 the conclusion of his paper on Camptonyx, are of interest : — 



"The littoral genus ^Siphonaria, which Dr. Gray places between 

 the Auriculidse and Cyclostomidae, is remarkable for the presence of 

 a deep siphonal groove on the right side. Again, the large Tertiary 

 fossil genus Valenciennia, Rousseau, supposed to have been an 

 inhabitant of brackish water, has a channel running from the under 

 side of the beak of the shell to the right side of the aperture, much 

 like the dorsal one of Camptonyx. It is supposed by M. Bourguignat 

 to serve as a sheath to a siphonal tube. It probably communicates, 

 as in Camptonyx, with the respiratory orifice, and does not necessarily 

 contain a special organ. The strong concentric ribs of Valenciennia 

 present a curious analogy to the rugose surface of Camptonyx.^'' 



Valenciennesia is a characteristic genus of the fresh- and brackish- 

 water Pontian deposits (= Congerien Schichten) which belong to the 

 uppermost part of the Miocene system, and which extend from the 



