436 Rev. M. J. Berkeley and Mr. Hoffman 



the first and second fold are a number of wrinkles.. The matrix 

 terminates close to the anus. 



Besides the organs above mentioned, there is a cylindrical body 

 consisting of a rather firm transparent jelly, disposed apparently in 

 layers, parallel to the rectum, and running along the duodenum as far as 

 the pylorus. Of this no excretory tube could be satisfactorily traced, 

 but it was supposed that it must secrete something necessary for the eggs. 



The brain consists of four ganglions. The two upper ganglions are 

 close together, as also are the two lower ones. The right upper ganglion 

 sends oft' on its own side two principal nerves beneath the oesophagus, 

 and one above it to the left. The left upper ganglion sends off two 

 behind; and in front both send off to the parts about the mouth several 

 nerves, of which the bindermost are forked at their origin from the 

 ganglions. The two lower ganglions supply the tentacula, and from 

 their lower part numerous branches penetrate the foot. 



From the whole of the preceding account it is evident that we have 

 before us an animal allied very nearly indeed to Trochus. Its external 

 appearance is precisely that of Turritella, with the exception that in 

 Turritella there is a membrane on the right side of the foot. The 

 digestive organs are very like those of the Trochus dissected by Cuvier, 

 The stomach would indicate that its food is either vegetable, or if animal, 

 from its complicated structure, and the thickness of its coat in parts, 

 something most probably of a crustaceous nature ; and the very small 

 powers of the mouth, ill fitted for constant gnawing, make it highly 

 probable that its habits may be exactly those of Adanson's species. 

 However this may be, there can be little doubt that they are most nearly 

 allied. The small Cerithium reticulatum of our coasts in external 

 structure is just the same, possessing appendages neither to the foot nor 

 mouth. 



