THE PLATES OF ANIMALS. 481 



Plate P. — 1, Area tetragond, with 1. a. its byssus. 2. Leda caudata, 

 and 2. a. the expanded disk of its foot. 3. Leda pygmcea. 4. 

 Nucida mideus. 5. Nucula tenuis. 6. Pecticncuhcs gli/cimeris, 

 Qi\\\cA pilosics on the plate. The drawing of 1. is by Mr. Alder ; 

 the others are from our own sketches after life. 



Plate Q. — 1. Cyclas rivicola. 2. Unio pictorum. Z. Anodonta cygnea, 

 with 3. a, its mantle-fringe. 4. Dreissena polymorpha, 4. a. and b. 

 dt'tails of its siphons, after sketches by Mr. J. de C. Sowerby. 5. 

 Mytilus edulis, and 5. a. part of its mantle-fringe. 6. Modiola 

 tulipa. 7. Crenella nigra (after a drawing by Mr. Alder). 



Plate R. — Lima hians (mider Tm-ton's name of Z. tenera). 1. and 2. 

 different views of the animal fully expanded. 3. its foot. 4. one 

 of the cirrhi highly magnified. The beautiful drawings from which 

 these figures were engraved, are among the many favours we owe to 

 the pencil and observation of our accomplished friend, Mr. Alder. 



Plate S. — 1. Pecten similis. 2. P. striatus, and 2. a. a portion of its 

 mantle highly magnified. 3. P. niveus, with 3. a. portion of its 

 mantle. 4. Avicula tarentina, drawn from a living Mediterranean 

 specimen (E. F.). 



Plate T. — 1. Ostrea edulis (this beautiful figure was most kindly drawn 

 and engraved from the living animal by Mr. J. de Carle Sowerby). 

 2. Anomia .ephippvum. 3. Sphcenia Binghami, from a drawing 

 by Mr. Spence Bate. 



Plate U. — 1. Terebratula caput-serpentis, 1. b. the under valve, and 

 1. c. the upper valve, laid open, from living specimens taken in 

 Loch Fyne. 2 Crania norvegica. 3. Hyalcea trispinosa, and 4. 

 Spirialis (after Souleyet), named Peracle on plate. 



Plate W. — 1. Panopa^a norvegica, after a drawing from the living 

 British specimen by Mr. Richard Howse. 2. Poromya granidata, 

 after a sketch by Mr. M'Andrew. 3. Appendicular ia, a slight 

 sketch from a British example. 



[Plates X, Y, Z, no such plates]. 



SERIES 11. 

 GENERA OF GASTEROPODA AND CEPHALOPODA. 



Plate AA. — 1. Patella {Patina) pellucida. 2. Aoncea testudinalis, 

 — 2. a. and b. one of the articulations of the tongue. 3. Pilidium 

 fidvuin, with 3. a. its head, showing the eyeless tentacles, and 3. b. 

 articulations of its tongue. 4. Propilidium ancyloide, with 4. a. 

 under side of its head, and 4. b. upper side of its head and position 



