378 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



where the base of attachment is wider, the reflection stouter, and the inner 

 cutting point becomes bifid. Tlie marginals are low, wide, the reflection 

 eqwuUing the base of attachment, the inner cutting point short, bluntly bifid, 

 the outer shorter and blunt, often bifid (PI. X. Fig. C). 



Tachea hortensis, Muller. 



Vol. III. ri. VIII. 



Shell imperforate, subglobose ; epidermis shining, smooth, oblivaceous-yel- 

 low, and often variously ornamented with rufous horizontal 



Fi" 263 

 '^' ' bands or lines ; whorls 5, convex ; spire somewhat elevated ; 



suture, at the extremity of the last whorl, curved towards 

 the aperture ; peristome slightly reflected, white, obsolete 

 on the base, with the margin thickened internally ; aperture 

 rounded, slightly contracted at the base by the thickening 

 T. hortensis. ^^^ indentation of the peristome ; umbilicus covered, in- 



dented ; base convex. Greater diameter 20, lesser 17 

 mill. ; height, 12 mill. 



Helix hortensis, MUller, etc. — Pfeiffer, Mon. Hel. Viv., III. 195. — Mrs. 

 Sheitard, Tr. Lit. Hist. Soc, Quebec, I. 193 (1829). — Gould, Invert., 172, 

 ed. 2, 429 (1870). — Binney, Terr. Moll., II. Ill, PI. YIII. — W. G. Binney, 

 Terr. Moll., IV. 51 ; L. & Fr.-W. Sh., L 181 (1869). —Morse, Amer. Nat., 

 I. 186, Fig. 16 (1867). 



Helix siibglobosa, Binney (formerly), Bost. Joum. Nat. Hist., I. 485, PI. XVI. 

 (1837). — DeKay, N. Y. Moll., 33, PI. II. Fig. 14 ; PI. III. Fig. 39. 



Tachea hortensis, Morse, Jouru. Portl. Soc, I. 10, Fig. 11 ; PI. IV. Fig. 12 

 (1864). — Tryon, Am. Joum. Conch., II. 321 (1866). 



An European species, introduced by commerce (?) to the northeastern por- 

 tion of North America. It is found on islands along the coast from Newfound- 

 land to Cape Cod, and on the mainland plentifully in Gaspe, C. E. ; also along 

 the St. Lawrence ; Vermont (?), Connecticut (?), etc. It also inhabits Green- 

 land and Iceland (see Morch, Am. Joum. Conch., IV. 45).' 



Animal : head and neck blackish, with a slight tinge of brown ; eye-pedun- 

 cles and tentacles smoky ; eyes black ; base of foot inky, posterior extremity 

 dirty flesh-color. Foot rather slender, terminating acutely. Respiratory fora- 

 men surrounded with a blackish circle. Genital orifice indicated by a black- 

 ish spot a little behind the right eye-peduncle. Length about twice the breadth 

 of the shell. (See Bost. Journ. Nat. Hist., L PI. VIII.) 



Having kept a large number of this species in confinement. Dr. Binney had 

 frequently an opportunity of noticing the manner in which the epiphragm is 

 formed, a process which seems not to have been heretofore correctly described. 

 The aperture of the shell being upwards, and the collar of the animal having 

 been brought to a level with it, a quantity of gelatinous matter is thrown out, 



