ANATINA. 65 



ANASTOMA or ANOSTOMA. Fischer, (from Am, ana, back- 

 wards ; Sro/xa, stoma, mouth) Fam. Colimacea, Lamark. A genus 

 of land shells so named from the singular circumstance of the 

 last whorl taking a sudden turn and reflecting the aperture up- 

 wards, so as to present it on the same plane with the spire ; so 

 that the animal walks with the spire of the shell downwards 

 resting on the foot. In other respects, the two species of which 

 this genus is composed, resemble other Helices ; and belong to 

 De Ferrusac's division " Helicodonta." Tomogerus is De Mont- 

 fort's name for this genus. A. depressum is represented in the 

 plates figs. 271, 272. The nearest approach to this genus will be 

 found in the fossil shell named Strophostoma, by Deshayes, 

 which, however, has no teeth in the aperture and is provided with 

 an operculum like Cyclostoma. South America. 



ANATIFER. Brug. Anatifa, Lam. This name, which signifies 

 Duckbearing, has been given to the shells commonly called Bar- 

 nacles, on account of an absurd notion entertained among the 

 ancients, that they inclose the young of the Barnacle duck, in 

 an embryo state. The beautiful bunch of jointed arms, the cilise 

 of which serve the purpose of agitating the water, so as to draw 

 in food by the current, were supposed to be the feathers of 

 the future bird. For a description of these shells, see Pente- 

 l asm is ; and fig. 34. 



ANATINA. Lam. {That which belongs to a duck) Fam. Myaria, 

 Lam. Pyloridea, Bl. — Descr. Thin, transparent, generally equi- 

 valve, inequilateral, transverse, marine ; hinge with a spoon- 

 shaped process in each valve, containing the cartilage. — Obs. 

 Some species included in the genus Anatina of authors, A. striata, 

 for instance, have not the spoon-shaped prominence, but in its 

 place a small, testaceous, moving appendage, connected with the 

 interior of the hinge. These are now separated, and form the 

 genus Lyonsia. The genus Naeara, Gray, is composed of Anatina 

 longirostrum, and similar species, which have neither the bony 

 appendage nor the spoon-shaped prominence. Mya is distin- 

 guished from Anatina, by the thickness of the shell, and also by 

 having the prominence only in the hinge of one valve. Fig. 69. 



