Pkoductus. mollusc a. 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, lb. 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. — Sower. Min. Conch, t. cccxviii. f. 2-6 ; and 

 P. sulcatus, lb. 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. — Oblong, 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. — Soujer. Min. Conch, t. cccxxii — In Magnesian Limestone. 



11. P. giganteus — Transversely oblong, with dilated sides and rugose irre- 

 gular sti'iae, longitudinally undulated or sulcated; larger valve gibbose. — 

 Amonites giganteus, Mart. Derb. t. xv. P. gig. Sotver. Min. Conch, t. cccxx. 

 — Carboniferous Limestone. 



12. V. crassus. — Rounded, longitudinally sulcated, ard striated; strife 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. cccxxu^^Carboniferous 

 Limestone. 



14. P. punctatus — Shell rounded, sliglitly 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— 

 Conchte 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. V.Jimbnatus — Shell slightly elongated, rounded, gibbous towards the 



apex, with rather distant transverse ridges; thinly spinous Sower. Min. 



Conch, t. cccclix. f. 1. — Carboniferous Limestone. 



16. v. 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 Carboniferous 

 Limestone. 



17. T. hemispJicericus — Hemispherical, longitudinally striated ; striae fine; 



lower valve very concave — Sower. Min. Conch, t. cccxxviii Carboniferous 



Limestone. 



18. P. comoides — Semicircular, gibbose, very finely striated; disk inflated; 



back straight, extending the whole width of the shell Sotver. Min. Conch. 



t. cccxxx. — Carbonifermis Limestone. 



19. P. /a<mJ»iJw.—Transverely oblong, depressed, coarsely striated ; beak 

 nuich incurved; hinge line very long — Sotver. Min. Conch, t. cccxxx.— C«r. 

 boniferous Limestone. 



