OF THE HALOLIMNIC FACXA OF LAKE TANGANYIKA. 341 



the southern third of the lake, and he considers that, in conchological 

 characters, it is identical with several marine Jurassic fossils, described 

 under Amherleya. He fiu'ther remarks that except for its widely 

 different shell, Bathanalia is structurally identical with Typhohia. 

 Referring to the diagnosis of Amherleya, quoted in p. 346, Moore says 

 that this would absolutely answer for Bathanalia. According to his 

 view the thin shell, the absence of all trace of epidermis, and the 

 character of the whorls, as well as the sculpture and character of the 

 mouth, are all essentially the same in Bathanalia as they are in 

 Amherleya. 



Judging from figures only, this is the most striking of all the 

 resemblances. I gather, however, that there are some differences in the 

 aperture. 



On p. 348, Moore has figured the back only of my specimen of 

 Amherleya orhignyana. The right hand upper figure on this page is 

 intended for an Amherleya. which I do not quite recognise. The two 

 lower figures represent Bathanalia, back and front. It is unfortunate 

 that no good front aspect of Amhei'leya is presented to the reader, for if 

 the aperture in Bathanalia. is correctly drawn, it does not possess the 

 straight pillar lip, coming forwards almost to a point, which is so 

 characteristic of Amherleya.. In all other respects the resemblance is 

 most striking, even to the angular outline of the outer lip, which in 

 Batlmnalia is prolonged into a short process. It should be observed, 

 however, that there is somewhat of an umbilical opening in Bathanalia^ 

 whereas the shell of A mherleya is entirely closed. 



Amherleya (including Eucyclus, which latter, if not a synonym, has a 

 close relationship) is eminently characteristic of the Lias. It comes up 

 from the Lower Lias, and culminates in the Inferior Oolite, especially in 

 beds having a Cephalopod facies, as in the Anglo-Norman basin. Occurs 

 also in the Great Oolite, and seems to have left this country with bed of 

 Corallian age."^ 



4. Limnotrochus thompsoni, Smith, with Littorina sulcata, Hehert and 



DeslGngcharaps. 



See pp. 233 and 349. It is also compared with Z. dorsetensis, Hudl. 

 In the possession of a black epidermis and in its general aspect 

 Limnotrochus thompsoni has a certain fresh-water character. The 

 aperture, however, is more like that of Littorina than of Trochus. The 

 trochiform outline of the shell and the ornamentation, especially the 



* Since w^riting the above, I have had an opportunity of inspecting a 

 specimen of Bathanalia through the courtesy of Mr. Da Costa. I am 

 more than ever impressed with the extraordinary resemblance of the 

 spire to that of Amherleya pagoda, but the character of the mouth is so 

 very difi'erent, that I conclude the resemblance of the spire to be 

 fortuitous. 



