GASTEROPODA. 



133 



Siphonaria. Soiv. (Liria Gray ; Trimusculus 

 Schmidt). — Shell resembling the Patella in shape, but 

 with an indented groove in the 

 interior, extending from the 

 apex to the margin, having the 

 appearance of a canal, or siphon, 

 which produces a slight projec- 

 tion at the edge. Animal hav- siphonana. 

 ing the head furnished before 



with two rounded lobes, which bear the eyes at their 

 upper side; no feelers: the mantle lengthened on the 

 right side (where the shell somewhat juts out) into a 

 tongue-formed lobe, which closes with a flap the avenue 

 to the lung cavity. — ■ About 30 species ; also fossil. 



It is difficult, at first sight, to distinguish this shell 

 from a Patella, the groove not being very perceptible ; 

 indeed, many authors class them together. They are 

 found on the coasts of South America, New Zealand, 

 India, and the Philippines. The animals appear to be 

 ornamented with various colours. 



Gardinia. Gray. (Mouretia Sow.). — Shell conical, 

 muscular impression a connected horse-shoe shape, no pro- 

 jection on the right side where the siphonal groove ends. 

 Animal only differing from that of Siphonaria by the large 

 head lobes being lengthened and more triangular, as well 

 as that the lobe is wanting in the mantle, which, in that 

 Mollusc, closes the avenue to the lung cavity. — 8 species; 

 also fossil. 



Found in the Mediterranean, Red Sea, and American 

 seas. 



Family 27. — ACMACACEA. 

 The animals have a snout-formed head ; two long, cy- 



K 3 



