438 
CONCHIFERA. 
Avicula Anglica. — The English Avicula. 
Plate LXXXV11I. fig. 11. 
Wing moderate, obliquely curved; yellowish fawn-coloured, 
with dark reddish-brown blotches; inside pearlaceous and irides¬ 
cent. One inch and a fourth long. Inhabits the Devonshire 
coast. 
Genus 24.—MALLE US.— Lamarck. 
Generic Character —Subequivalve, rugged, distorted, fre¬ 
quently elongated; sublobate at the top ; beaks small, diverging ; 
hinge without teeth, with an elongated conical furrow under the 
beaks; ligament subexternal, short, placed in the sloping area, 
at the top of the valves. 
Malleus albus. — The White Malleus. 
Plate LXXXVII1. fig 12. 
Trilobate •, base of the lateral lobe prolonged, without a sinus, 
the base and the pit for the ligament not distinct; white with 
transverse undulations. Four inches long. Inhabits the Aus¬ 
tralian seas. 
Genus 25. —PERNA.— Lamarck. 
Generic Character. — Subequivalve, flattened, slightly distort¬ 
ed, of a lamellar texture; hinge linear, marginal, and many 
toothed, which are furrow-like, parallel, and transverse, not 
inserted in the opposite furrows, between which the ligament is 
inserted; sinus for the byssus somewhat gaping, and placed un¬ 
der the extremity of the hinge, 
Perna ephippium. — The Saddle Perna. 
Plate LXXXVIII. fig. 13. 
Compressed, suborbicular; left valve produced, the margins 
acute ; purplish-brown on the outside, and pearly within. Four 
inches long. Inhabits the Indian seas. 
Genus 26.—CRENAT ULA.— Lamarck. 
Generic Character. — Subequivalve, flattened, somewhat dis¬ 
torted and lamellar; with an opening for the byssus; hinge 
lateral, linear, margined, and crenated; the crenulations in a 
