338 Mr. W. H. Benson on Camptonyx. 



delay publication until an investigation of the animal can take 

 place. 



Cheltenham, 10th April, 1858. 



I have much pleasure in adding the following note embodying 

 the results of an examination which Mr. S. P. Woodward has 

 had the kindness to undertake. 



Mr. Woodward writes — " The shell appears to be closely allied 

 to AncyluSy but differs in being dextral (in which respect it agrees 

 with the subgenus Velletia), and especially in having a respira- 

 tory channel or siphon on the right side." Subsequently, Mr. 

 Woodward states his belief that Camptonyx differs considerably 

 from Ancylus, which he had not at hand for comparison, and 

 adds the following description of the animal, as viewed under 

 the microscope : — 



" The respiratory orifice is quite on the edge of the mantle. 

 The tentacles are rather conical than angular, and the mouth 

 appears to me rather peculiar, unlike Physa and Lymncea. The 

 upper mandible is conspicuous, slightly lobed, but destitute of 

 the ridges seen in the Helicidse, and of the lateral elements 

 which are added in Lymncea. The lingual ribbon is -036 long 

 and -014 wide, with 86 rows of teeth, 87 in a row ^^^^^^; they 

 have simple obtuse hooks, as in Ancylus : the central row only 

 differ in being symmetrical; the laterals diminish gradually 

 from the 14th to the 43rd, and a second (outer) cusp makes its 

 appearance, and increases until the three near the margin are 

 regularly bicuspid. This tongue is more like Ancylus than any 

 other, but differs from it in the absence of those unarmed mar- 

 ginal plates which give a peculiar appearance to the lingual 

 ribbon of Ancyltis, and are still more conspicuous in Velletia. 

 If I had seen nothing else but the tongue, I should have pro- 

 nounced it a new subgenus of Ancylus.'^ 



Taking everything into consideration, I think that I am jus- 

 tified in regarding the shell as the type of a new genus. The 

 belief that the habits of the animal are terrestrial, and that 

 abundant moisture, such as occurs periodically in a tropical cli- 

 mate, without actual immersion in water, suffices for its support 

 during its season of activity, appears to me to be confirmed by 

 the opening of the respiratory orifice into the lateral channel of 

 the shell*. This conduit may perform the same office as the 



* A subsequent examination of the piece of rock, under a lens, revealed 

 a minute globose Succinea, probably the young of the large species men- 

 tioned, firmly adhering among the remaining specimens of Camptonyx, 

 and proving that these two genera exist in the same medium. 



