128 
MOLLUSCA. 
Atrypa. 
Found in the Aymestry Limestone at Wallsgrove quarry; 
Sunny Hill Bank, Ludlow; and also in the Upper Ludlow 
Rock, Fownhope; and Dog Hill, Ledbury. 
2. Atrypa affinis,—T he Allied Atrypa, pi. LIV.* fig. 
L 2. 
Atrypa affinis . Sowerby, Sil. Syst. p. 610 and 614, pi. 6, 
fig. 5. Atrypa reticularis, Dalman, Act. Holm. 1827, p. 127, 
pi. 4, fig. 2. Hisinger, Pet. Succ. p. 75, pi. 21, fig. 11. Tere- 
hratula affinis , Sowerby, Min. Conch. IV. p. 24, pi. 324, 
fig. 2. Terebratula prisons, Von Buch, p. 71. Schl. pi. 17, 
fig. 2. 
Orbicular, with strong, deep, regular, radiating stria); upper 
valve gibbous, with an obtuse, elevated sinus in front, filled at 
the base with the longer-shaped sinus of the opposite valve; 
lower valve nearly flat. 
Found in the Carboniferous Limestone at Horncastle; the 
Melvern Hills; very common in the Upper Silurian Rocks; 
occurs in the Aymestry Limestone at Ludlow and Aymestry, 
and many other places; and in the Wenlock Limestone at May 
Hill, Eastnor Park; Abberley Lodge; and Malvern Hills. 
3. Atrypa aspera.—T he Rough Atrypa, pi. LIV. fig. 
49, 50. 
Atrypa aspera. Dahnan, 1. c. p. 128, pi. 4, fig. 3. Hist. 
Pet. Suec. p. 75, pi. 21, fig. 12. Sowerby, Sil. Syst. p. 623, pi. 
12, fig. 5. Terebratula asper , Schloth, Nat. Pet. 1822, p. 68, 
pi. 18, fig. 3. 
Orbicular; valves equally convex; with the base slightly 
truncated; surface covered by numerous, radiating furrows, 
increasing in number by intermediate ones as they approach 
the margins, these are crossed by undulating lamina). Diame¬ 
ter half an inch. 
Very closely allied to A. affinis, but distinguished from it by the valves 
being equally convex, and their form being more orbicular. 
Found in the Wenlock Limestone, Wenlock Edge. 
4. Atrypa tenuistriata—T he Thin-striated Atrypa, pi. 
LIV. fig. 80. 
Atrypa tenuistriata. Sowerby, Sil. Syst. p. 623, pi. 12, fig. 
3. Terebratula obtusa, lb. Linn. Trans. XII. p. 516, pi. 28, 
fig. 3, 4. 
Slightly ovate transversely, gibbose; beaks small, a little pro¬ 
minent, considerably waved, bent, and close to each other; base 
with a narrow protrusion; surface with fine, longitudinal stria). 
Diameter one inch and three-quarters. 
Nearly allied to A. oblata, but will be distinguished by the position of 
the beaks. 
Wenlock Limestone, Dudley, Wenlock, Abberley, Aymestry; 
May Hill and the Lye, near Stourbridge. 
5. Atrypa compressa.—T he Compressed Atrypa, pi. 
LIV. fig. 44, 45. 
Atrypa compressa. Sowerby, Sil. Syst. p. 629, pi. 13, 
fig. 5. 
Slightly transverse, ovate, somewhat compressed, smooth ; 
base with a very slight indentation; beaks small, and a little 
produced; sides rounded. Length five lines; breadth six lines. 
Wenlock Shale, Nash and Woodside, near Presteijjn. 
9 O 
6. Atrypa linguifera-— The Tongue-shaped Atrypa, pi. 
LIV. fig. 21,22. 
Atrypa linguifera. Sowerby, Sil. Syst. p. 629, pi. 13, 
fig. 8. 
Orbicular, nearly globular, very convex, smooth; beaks large, 
unequal, that of the larger valve considerably produced; base 
elevated, tongue-shaped. Length seven lines; depth of valves 
united seven lines and a half. 
Wenlock Shale, Stumps Wood; Delves Green; and Valley 
of Woolhope. 
7. Atrypa depressa —The Depressed Atrypa, pi. LIV. 
fig. 78, 79. 
Atrypa depressa. Sowerby, Sil. Syst. p. 629, pi. 13, fig. 6. 
Transversely obovate, compressed, smooth; sides depressed; 
base much elevated, the elevated portion square; beaks une¬ 
qual; with three or four, nearly obsolete, longitudinal furrows 
along the middle. Length four lines; width five lines. 
Wenlock Shale, Delves Green and Stumps W r ood. 
8. Atrypa rotunda —The Rounded Atrypa, pi. LIV. 
fig. 64, 65. 
Atrypa rotunda. Sowerby, Sil. Syst. p. 629, pi. 13, fig. 1. 
Almost orbicular, very convex, and smooth; base elevated ; 
beaks small, equal; surface with fine, longitudinal, obscure fur¬ 
rows towards the base. Length seven lines; width seven lines 
and a half. 
W 7 enlock Shale, Escarpments of Wenlock Edge. 
9. Atrypa cassidea. —The Little-helmet Atrypa, pi. 
LIV. fig. 53. 
Atrypa cassidea. Dalman, pi. 5, fig. 5. Phillips, Pal. Fos. 
p. 83, pi. 34, fig. 148, a, b, c. 
Oblong-ovate, ventricose, smooth; beak large; sides and base 
rounded; a few indistinct lines of growth on both valves. 
Devonian Limestone, South Devon and Newton. 
10. Atrypa cuboides. —The Slightly-cubular Atrypa, pi. 
LIV. fig. 4, 5. 
Atrypa cuboides. Sowerby, Geo. Trans. V. 2nd series, pi. 
56, fig. 24. Phillips, Pal. Fos. p. 84, pi. 34, fig. 150. 
Subglobose; base elevated, and very flat on the surface; 
margin with a deep square sinus; beak small, acute; lower 
valve small, almost flat, with a large, produced, square append¬ 
age, filling the sinus in the upper one; surface with numerous, 
narrow ribs, emanating from the beaks, with about fifteen on 
the mesial sinus, more elevated than the others, those on the 
sides greatly curved, and on the base parallel. 
Devonian Limestone, Plymouth ; and Hope, near Torquay. 
11. Atrypa expansa. —The Expanded Atrypa, pi. LIV. 
fig. 70, 71, and pi. LII. fig. 5, Spirifer expansa. 
Atrypa expansa. Sowerby, Min. Conch. VII. p. 14, pi. 617, 
fig. 1. Spirifera expansa, Phillips, Geo. York. 
Transversely subovate, somewhat inflated; base nearly 
straight; destitute of a mesial fold; surface covered with 
broad, striated, imbricated fringes; beak small, produced, and 
incurved. 
When this species is deprived of its fringes, it presents the appearance 
and answers to the description which 1 have given of it, p. 112, pi. LII. 
fig. 5, uuder the name of Spirifer expansa. It is distinguished from A. 
fimbriata by its even and inflated surface. 
Mountain Limestone, Bolland. 
12. Atrypa planosulcata* —The Flat-furrowed Atrypa, 
pi. LIV. fig. 81, 82, and pi. LII. fig. 4. 
Atrypa planosulcata. Sowerby, Min. Conch. VII. p. 15, pi. 
617, fig. 2. Spiriferaplanosulcata , Phillips, Geo. York. II. p. 
220, pi. 10, fig. 15. See also p. 112. 
