SPECIAL ANATOMY. 1<)9 



Helix ; H. alholabris^ H. tht/roidus, H. sayi, H. tri- 

 dentata, H. fallax, H. 2Jcdlicita, H. llgera, H. intertexta, 

 H. siippressa, H. auriculata, H. elevata, H. profunda, 

 S. concava, H. fidiginosa, H. perspectiva, H. alternata, 

 S. cellm'ia, H. exoleta, IT. multUineata, H. hirsuta, H. 

 soUtaria, S. dentifera, H. arborea, S. pulchella, JS. 

 berlanderiana, S. gularis, S. injlecta, S. tezasiana. 



BuLiMUS ; B. fasciatus, B. decoUatus, B. virgidatus, 

 B. dealbatus, B. caribbceorum. 



Pupa ; P. incana. 



SucciNEA ; aS". obliqua. 



Glandina: Cr. truncata. 



Chapter i. — general remarks upon the exterior form 



AND structure OF THE TERRESTRIAL NAKED GASTERO- 

 PODA. 



Upon examining a Limax or an Arion, we find it com- 

 posed of a thick, vermiform body, with a broad, ribbon- 

 like, pedal disc, rmming the whole length of its inferior 

 surface. The anterior, obtuse extremity forms the head ; 

 and from it protrude four retractile tentaculse, upon the 

 outer side of the tip of the two superior, or longer of 

 which, is placed the eye. The mouth is situated at the 

 antero-inferior part of the head ; and immediately below 

 it is a deep depression, or bhnd sac. The posterior part 

 of the body forms the tail, and is acute. Upon the 

 antero-superior part of the body is placed the mantle, 

 which covers the pulmonary chamber, and contains within 



