MOLLUSCA. 
•125 
head with two acute tentacula, and the eyes situated at their 
exterior base; branchiae placed under the mantle and around the 
body; anal and generation orifices situated on the right anterior 
side.—Shell univalve, not spiral, concave within, simple, entire, 
with the vertex anteriorly inclined. 
Patella vulgata. —The Common Patella, or Limpet. 
Plate LXXXVII. fig. 15. 
Oval, conic, or a little depressed; outside green or brown, 
sometimes radiated with various colours; having divergent stride 
and concentric wrinkles; inside glossy, iridescent, with yellow 
or fawn-coloured, purple, blue, or brown radiations. Two inches 
long. Inhabits the coasts of Europe. 
Genus 25. — CHITON.'— Linnceus. 
Generic Character. — Body creeping, ovate-oblong, convex, 
round at both extremities ; marginated with a coriaceous skin •, 
the back covered by a longitudinal series of testaceous, trans¬ 
verse, imbricated, and moveable plates; head before, sessile, 
with the mouth placed below; destitute of tentacula or eyes; 
branchiae placed round the body, under the margin of the skin; 
anal orifice at the posterior extremity. 
Chitonfascicularis .— The Fasciculated Chiton. 
Plate LXXXVII. fig. 13. 
Eight imbricated valves, nearly smooth, slightly carinated, 
and rounded at the margins, with a thick tuft of hair between 
the junction of the valves, having five on the top of the upper 
valve, and three on the base of the lower one. Three-fourths 
of an inch long. Inhabits the British coasts. 
Genus 26.—C HIT O NE LL US.— Lamarck . 
Generic Character. —Body creeping, elongated; middle of the 
back provided its entire length with a multivalve shell; the alter¬ 
nate pieces for the most part longitudinal; sides naked ; branchiae 
disposed around the body; foot cleft longitudinally by a deep 
furrow. 
2 M 3 
