32 ANATINID.E. 



Tellina coruscans of Scacchi, and Pandora^ aquivalvis 

 of Philippi. It likewise appears to be the My a membra- 

 nacea of Gmelin, from Miiller's 'Prodromus/ judging 

 from the description ; although Dr. Morch informs me 

 that the shell figured in Olafsen and Povelsen's Voyage 

 to Iceland, and referred to by Miiller for this species, 

 represents Astarte sulcata, var. elliptica. 



Family XVIII. ANATT'NID^E, D'Orbigny. 



BODY oval or oblong : mantle very thin : tubes long ; orifices 

 fringed : gills one on each side : palps two on each side : foot 

 lanceolate or tongue-shaped, small, and compressed. 



SHELL oval or oblong, slightly inequivalve, gaping more or 

 less on each side, and truncated at the posterior end : beaks 

 small, inclining to the posterior side, mostly fissured : epidermis 

 slight : ligament sometimes external and situate at the posterior 

 side, besides invariably an internal cartilage, which is contained 

 in a pit or receptacle under the beak in each valve : hinge fur- 

 nished with a free crescentic ossicle, placed across the hinge- 

 line at the anterior side of the beaks ; otherwise toothless : 

 pallial scar narrowly but deeply sinuated : muscular scars 

 small and irregular. 



The typical genus, Anatina, is a native of tropical seas. 

 It may be distinguished from Thracia in the tubes being 

 united, the pearly nature of the shell, and in having 

 inside an oblique falciform rib, proceeding from the car- 

 tilage-pit towards the posterior side in each valve. This 

 process is formed apparently in consequence of the 

 beaks being fissured in that direction, and it serves as 

 an upright girder to strengthen the shell. Something 

 of the same kind, however, may be observed in most 

 species of Thracia. The genus Anatina of Schumacher 

 is different from that of Lamarck, and belongs to the 

 Mactridce. The Anatinidte usually frequent a sandy or 



