Venerupis. MOLLUSCA. VENERIDiE. 
451 
Gen. CXXIX. VENERUPIS. — Transverse, anterior side 
short ; teeth three, erect, approximate and parallel ; sy- 
phon impression large. 
538. V. perjbrans. — Shell subrhomboidal, concentric striae, 
forming ridges retrally, and crossed by fine longitudinal ones ; 
teeth slender, and slightly recurved. 
Venus per. Mo7it. Test. Brit. 127- — 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. Syst. i. 1128. Don. Brit. Shells, t. xxix. Mont. Test. 
Brit. 108. — Petricola Irus. Turt. Biv. Brit. 26.— In Limestone Bocks, 
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, v^here 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. 
JVood, 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 striae, 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, Pemz. 
Brit. Zool. iv. 96. t. Ivii. f. 53. Mont. Test. Brit. 124. Tv/rt. 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 striae, 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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