Venerupis. MOLLUSCA. VENERIDiE. 451 



Gen. CXXIX. VENERUPIS. — Transverse, anterior side 

 short ; teeth three, erect, approximate and parallel ; sy- 

 phon impression large. 



—538. V. per/brans. — Shell subrhomboidal, concentric stria?, 

 forming ridges retrally, and crossed by fine longitudinal ones ; 

 teeth slender, and slightly recurved. 



Venus per. Mont. Test. Brit. 1 27-— Venerupis per. Turt. Turt. Biv. 



Brit. 29 Lodged in Limestone. 



Length about an inch ; breadth two inches and a half; white or brownish, 

 with ziz-zag purple stripes, anteriorly short and truncate; dorsal and ventral 

 margins nearly parallel ; two of the teeth cloven ; the syphon-mark broad, 

 and adjacent to the marginal impression. 



— . 539. V. Irus. — Suboval, with elevated concentric reflected 

 ridges, the interstices striated longitudinally. 



Donax Irus, Linn. Svst. i. 1128. Don. Brit. Shells, t. xxix. Mont. Test. 



Brit. 108 Petricola Irus. Turt. Biv. Brit. 26 — In Limestone Rocks, 



which it perforates. 

 Length half an inch, breadth three quarters ; white, with a tinge of brown ; 

 variable in its outline, usually truncate anteally, and rounded retrally, with 

 the dorsal and ventral margins nearly straight, and parallel ; the ridges are 

 distant ; the syphons, according to Montagu, are long, slender, white, and 

 pellucid, united to near the extremity, where the diverge become pink co- 

 loured, with openings ciliated with feathered fibres. 



~540. V. pullastra. — Transversely oblong with concentric 

 striae, becoming rough at the retral extremity, minutely striated 

 longitudinally ; syphon-mark broad, and parallel with the mar- 

 ginal impression. 



Wood, Linn. Trans, vi. t. xvii. f. 13, 14 — Venus pull. Mont. Test. Brit. 

 125. Turt. Biv. Brit. 159 — In Clay, common. 



Length an inch and a half, breadth two inches ; white, tinged with brown 

 or purple, especially at the retral extremity, where it is slightly truncated. 



— 541. V. decussata. — Transversely oblong, with concentric 

 and longitudinal stria?, becoming tubercular on the retral extre- 

 mity ; syphon-mark receding from the marginal impression to- 

 wards the centre of the shell. 



Concha quasi-rhomboides, List. An. Ang. 171. t. iv. f. 20. Conch. 



t. ccccxxiii Venus decuss. Linn. Syst. i. 1135. — V. littorata, Penn. 



Brit. Zool. iv. 96. t. lvii. f. 53. Mont. Test. Brit. 124. Turt. Biv. 



Brit. 158. t. viii. f. 10 — English Shores. 

 Length two, breadth three inches ; principally distinguished from the pre- 

 ceding by superior size and strength, greater coarseness of strise, a more dis- 

 tinct impression in front of the beaks; the position of the syphon-mark, and 

 the syphons themselves, which are separate nearly to their origin in this, 

 while they are connected almost their whole length in V. pullastra, furnish 

 internal marks of difference, easily detected. 



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