PRODUCTUS. 
MOLLUSCA. SESSILIA. 
379 
7. P. Martini. — Semicylindrical, convex above, with a flattened front, 
deeply striated ; a few spines ; lesser valve nearly flat, deeply inserted ; hinge 
line equal to the width of the shell — Ammonites prod. Mart. Derb. t. xxii. 
f. 1,2, 3. P. Martini, Sower. Min. Conch, t. cccxvii. f. 2, 3, 4 ; and P. concin- 
nus, Ib. t. cccxviii. f. i. — In Carboniferous Limestone, common. 
8. P. lobatus Convex valve with a mesial groove ; spines few ; the ribs 
coarser, and the sides more compressed than the preceding species, with which 
it may be readily confounded.— <S'ower. Min. Conch, t. cccxviii. f. 2-6 ; and 
P. sulcatus, Ib. t. cccxix. f. 2 — In Carboniferous Limestone. 
9. P. horridus. — Quadrangular, with a large furrow along the middle, ear- 
ed, thorny ; ears prominent, subcylindrical ; beak much incurved, large. — 
Sower Min. Conch, t. cccxix. f. 1. — In Magnesian Limestone. 
10. P. humerosus.-^Ohlong, squarish, depressed, striated, spinose ? or his- 
pid ? hinge line less than the width of the valve ; in the larger valve are two 
very deep cavities near the beak, and a third connected with the beak ; front 
flattish. — Sower. Min. Conch, t. cccxxii.. — In Magnesian Limestone. 
11. P, giganteus — Transversely oblong, with dilated sides and rugose irre- 
gular striae, longitudinally undulated or sulcated ; larger valve gibbose. — 
Anionites giganteus. Mart. Derb. t. xv. P. gig. Sower. Min. Conch, t. cccxx. 
— Carbmiferous Limestone. 
12. V. crassus. — Rounded, longitudinally sulcated, ard striated; striae tu- 
bercular ; sides not dilated.- — Ammonites crassus, Mart. Derb. t. xvi. Car- 
boniferous Limestone. 
13. P. personatus. — Hemispherical, irregularly striated, beneath very con- 
cave ; within the larger valve are three deep cavities, one connected with 
the beak, and two remote — Sower. Min. Conch, t. cccxix.— Carboniferous 
Limestone. 
14. P. punctatus. — Shell rounded, slightly elongated, with a shallow mesial 
depression transversely sulcated ; the anterior part of the furrows and the 
ridges thickly covered with long cylindrical spines, concealing the shell.— 
Conchae pilosae, Ure, Ruth. 316. t. xv. f. 7* Anomites punctatus. Mart. 
Derb. t. xxxvii. f. 6, 7, 8. P. punct. Sower. Min. Conch, t. cccxxiii. — -In Car- 
boniferous Limestone. 
15. Y.fimbriatus — Shell slightly elongated, rounded, gibbous towards the 
apex, with rather distant transverse ridges; thinly spinous — Sower. Min. 
Conch, t. cccclix. f. 1. — Carbmiferous Limestone. 
16. P. semireticulatus. — Semiorbicular,^with a shallow mesial depression ; 
longitudinally striated, the striae rude, strong, and unequal ; transversely 
wrinkled. — Anomites semi. Mart. Derb. t. xxxii. f. 1-4.— In Carboniferms 
Limestone. 
17. V. hemisphwricus — Hemispherical, longitudinally striated ; striae fine; 
lower valve very concave — Sower. Min. Conch, t. cccxxviii. — Carbmiferms 
Limestone. 
18. P. comoides — Semicircular, gibbose, very finely striated; disk inflated; 
back straight, extending the whole width of the shell — Sower. Min. Conch, 
t. cccxxx. — Carboniferous Limestone. 
19. V. latissimus. — Transverely oblong, depressed, coarsely striated ; beak 
much incurved; hinge line very long.-— Sower. Min. Conch, t. cccxxx. — Car- 
boniferous Limestone. 
