57 



spicuons ash groy, rounded, radiatinfj, slightly rugose ribs, 

 about 4C iu number, interstices dark brown, concave, with 

 smaller ribs occasionally, which reach half up the shell. 

 Margin acute and finely undulating Interior regularly 

 marked with dark brown and white lines, the latter concave 

 and corresponding with the ribs, the brown marks becoming 

 broader towards the edge and often bifurcating, spatula badly 

 defined and clouded reddish brown, siphon not always de- 

 fined 



The animal is a citron yellow beneath ; above dusky, speckled 

 with yellow. The head is separated from the foot by a deep 

 transverse fissure. The base of the head is pale neutral tint. 

 When the mouth is closed it appears as a reddish brown spot. 

 The lower lip is yellowish, and when closed is like a longitu- 

 dinal fissure. As it opens it becomes crescentic. The upper lip 

 is then seen. It is arched ; fine reddish brown above, with 

 yellow cirrhi below. The odontophore is protruded from this, 

 and moves up and down with an ordinary licking movement. 

 The appearance it presents is that of the finger of a glove with 

 the end pushed in upon itself, and the crowded edges 

 of the tube thus formed brought together by the drawing in of 

 the top until they unite in a rounded point, which is then 

 drawn up. The pushing out and drawing in of the top of the 

 *' finger " from within is the manner in which it feeds. Thus 

 the free end of the tube is apparently brought backwards and 

 forwards, and the food triturated and carried into the oesopha- 

 gus. 



No eyes are visible, though Messrs. Quoy and Gaim. say they 

 detected them above. They would be of no use above, as they 

 would touch the shell. The aperture of the siphon is the 

 same as in the last species. The process of the mantle which 

 forms a kind of operculum, is often protruded a considerable 

 distance from the shell. Messrs. Q. and G. say, " A little 

 in front of the siphon is the female organ, and on the right 

 side of the head the male, where the tentacle would be if there 

 were one. These holes are very difficult to see. When the 

 animal is taken from the shell it is found attached by a horse 

 shoe muscle running round the posterior half of the shell 

 above the mantle and foot. The siphon is seen as a tube run- 

 ning in a sinuous form through the pulmonary sac. By its 

 side runs the intestine, which continues round the posterior 

 part of the foot, and then disappears under the liver, and the 

 ovary, which is often the largest organ, and of a bright salmon 

 colour. The intestine makes many convolutions in the liver. 

 The buccal mass is like the preceding species with the same 

 kind of cesophagus, and, according to the Messrs. Q. and G., 

 two large salivary glands below. The same authors say that 

 the oviduct is carried under the uterus, which has the shape 



