456 



SUPPLEMENT. 



Fam. 13. Pahcdlnidcp : lingual teeth 3. 1. 3. (p. 138). 

 Paludina. Paludomus ? Ampullaria. Valvata. 



Fig. 249. Ampullaria globosa. (Wilton.) 



The lingual uncini of Paludina and Valvata are denticulated; in Am-i 

 pullaria the first and second uncini are tricuspid. 



Fam. 14. Utorinidce -. teeth 3. 1. 3. (p. 134). 



Litorina. Tectaria. Modulus, 



Fossarus. Narica. Solarium ? 



Lacuna. Litiopa. Eissoa. 



The teeth of Phonis are like those of Atlanta. (Mdrch.) 



Eisella. 

 Phorus ? 

 Truncatella, 



The lingual canal of the periwinkle passes from the oack of the mouth ( 



under the CEsophagus for a short distance, then turns up on the right side \ 

 and terminates in a coil (like spare rope) resting on the plaited portion qZ. 



the gullet. It is 1\ inches long, and contains about 600 rows of teeth; •■ 



the part in use, arming the tongue, comprises about 24 rows.* The \ 



* The opposite figure shows the manner in which a gasteropod may be laid out for \ 



examination, underwater; the body requires to be fixed, and the cut edges of tha i 



mantle to be kept open with needle points. A convenient trough may be made of a ' 



plain earthenware soap-dish, by cutting a piece of sheet-cork (such as bootmakers ' 



use) to fit the bottom, and fixing it to a piece of sheet-lead of the same size with a * 



couple of India rubber bands. The instruments required for dissecting are simply a • 



pair of fine pointed scissors, a few broken needles, a penknife, or scalpel, and a pair ^ 

 of forceps with fine curved points. 



