History of British animals - University of Guam Marine Laboratory

Pholas. MOLLUSCA. PHOLADiE. 457555. P. tubercidatus.— Shell open at the anterior end, with arough tubercle on the margin above the teeth, and a singleoval calcareous plateat the hinge extending to the anteal extremity.Turt. Biv. Brit. v. t. i. f. 7, 8 Torbay.Length three-quarters of an inch, breadth an inch and a half; white ; frontof the shell slightly elongated into a beak anterior ; compartment with roughribs, which gradually disappear towards the retral truncated extremity.556. P. conoides.— Transversely elongated, anteal divisionshort, tumid, rounded, the retral division produced and subcompressed.Parsons, Phil. Trans. 1765,i. t. 1.— P. striatus, Linn. Syst.i. 1111P. nanus, Pult. Dorset. 27. — P. stri. Don. Brit. Shells, t. cxvii. Moid.Test. Brit. 26. Turt. Biv. Brit. 11—In ship planks.Length half an inch, breadth an inch ; ridges in the anteal compartmentcrowded, rough in the retral wider and ; smoother, well marked along thefurrow ; nearly closed retrally ;when young, very open anteally, and beaked,but filling up with smoother shell (like P. papyracea) towards maturity ; onelarge rounded accessory plate over the hinge, behind which is a lengthenedone, and a third connecting the ventral margins of the shells a ; long slendercurved tooth in each valve.** The valves not divided by a groove.— 557. P. dactylus:— Conically transverse, with concentric,waved, muricated ridges, having longitudinal grooves, most conspicuousanteally ; margin above the beaks reflected, circular,with four accessory plates.P. striatus, 'List. Conch, t. ccccxxxiii. Anat. t. xix. f. 1 ,2—P. dact.Linn. Syst.i. 1110. Borl. Corn. 278. t. xxviii.-xxxi. Mont. Test.Brit. 20. Turt. Biv. Brit. 8—In rocks and submarine trees.Length sometimes 2 inches, and breadth 7 ;wide and open before ; slightlycompressed behind ; shell in front of the hinge produced into a kind ofbeak, with the edge thin and reflected.— 558. P. parvus.— Shell open, and produced into a beak anteally,with a smooth tubercle on the margin above the teeth,and a singleaccessorial valve at the hinge.Mont. Test. Brit. 22. t. i. f. 7, 8. Turt. Biv. Brit. 9—Submarine woodon the south coast of England.Length fths, breadth 1^ inches ; transversely striated, with longitudinalridges anteally the anteal opening ;is oval, and the fold above the beaks destituteof cells.Montagu is inclined to consider this shell as the P. parvus ofPennant, (Brit. Zool. iv. 77- t. xl. f. 13.) though it is not improbable that itis related to the young of P. papyracea.559- P. candidus.— Shell nearlyclosed anteally;a toothlikeprocess on the hinge ascending obliquely and retrally;margin above the hinge reflected, and covered with an elongatedaccessorial plate.Concha Candida, List. An. Aug. 193. t. v. f. 39. Conch, t. ccccxxxv—P.