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DIVISION XIX. LlNGUIACEiE. 



GENERA. 



1 ? OrmculA. Lam. M. 



Sub-orbicular, inequi- 

 valved, lower valve very 

 thin and flat, adhering to 

 marine bodies, upper 

 valve sub-conical, beak 

 more or less elevated. 

 Fig. 97. 



2. TEREBRATULA.2?rWg\M. 



Inequivalved, regular, 

 sub-trigonal, attached to 

 marine bodies by a short 

 tendinous pedicle ; the 

 largest valve with the 

 beak advanced, frequently 

 curved, pierced at the 

 summit by a round hole 

 or slope ; 2 ramifying and 

 almost bony appendages 

 within, slender, forked, 

 and differently branched, 

 springing from the disk of 

 the small valve, and 

 serving as a support to 

 the animal, (2) Fig. 98. 



a. Shell smooth, without striae or longitudinal furrows. 

 f. .. longitudinally furrowed. (2) 



Hinge not apparent, 



(1) The lower valve, which I have not been able to procure or figure, is some- 

 times so thin that it is scarcely perceptible. The European seas are said to 

 produce a small species. Is it a bivalve, or a Hipponyoc? 



■ (2) They appear to inhabit deep seas, for the fossil species exist in secondary 

 formations, with Ammonites, Gryphitcs, Belcmnitcs, etc. Many, however, have 

 been found in a recent state. M. Valenciennes has observed, that the hole of 

 the beak of the larger valve is generally round, and when it offers only a longi- 

 tudinal notch, it is from the absence of two small lateral and accessory pieces, 

 which, when united, complete the opening; this hole is also sometimes completed 

 by the edge of the smaller valve. The little tendinous cord which proceeds from 

 the hole of the T. Caput-serpentis, divides at the end into a bunch of byssiform 

 filaments which serve to fix the animal to bodies under the water. Foss. in 

 Gravel and Alluvial Clay, Sand, Crag Marl or Soft Limestone, Upper and Lower 

 Chalk, Chalk Marl, Green Sand, Bedford Limestone, Clay under Limestone, Great 

 Oolite, Under Oolite, Fuller' s-earth Rock, Blue Murl, Marston Marble, Blue Lias, 

 Coal Shale, Limestone Rock, Mountain Limestone, Derbyshire Peak Limestone, at 

 Meudon^ Trowre, St. Saturnin, Mans, Domfront, Valogne, Plaisance, Bourges, 

 Grignon, Turin, Cologne, Havre, Coulaines, Mont-Morius, Maeslrichl. 



