Fig. 
Fig. 
Fig. 
Figs. 
Fig. 
PLATE NII. [Pate 23.] 
SECTION 2.—PTERYGOTUS. 
1. Plerygotus ludens?s. Fixed ramus of the antennary chela. 
2. A smaller specimen of the same. 
3. The metastoma of this species (or possibly of P. gigas). 3a. The sculpture magnified. 
4, 5. Imperfect appendages (abdominal ? or thoracic ?). See also Fig. 16. 
6. The penultimate joint of an ectognath (P. gégas ?). 
- 
The above are all from the bottom beds of the Old Red Sandstone, or the ‘ Passage Beds’ 
into the Upper Ludlow Rock, at Ludlow. The following are from the Downton Sandstone, 
or Upper Ludlow Rock. 
Fig. 
Fig. 
Fig. 
. 28. Abdominal segment f ; : 
. 29. The basal joint of an ectognath. From the same formation and cabinet. 
. 30. Fixed ramus of the antennary chela. From the same formation and cabinet. 
. 31. A metastoma. From the same formation. (Museum of Practical Geology.) 
7. Prerygotus problematicus. The fixed ramus of the antennary chela. Whitcliff, 
Ludlow? 
8. The distal end of the same part. Downton Sandstone, Kington. (Mr. Banks’ 
cabinet.) 
9. A portion of the same ramus of a larger specimen. Upper Ludlow Rock, Ludlow. 
(Mr. J. Harley’s cabinet.) 
. 9*. A large serrated tooth, belonging to the (free?) ramus of a chela. Copied from a 
figure in the Quart. Geol. Journal, vol. viii. plate 21. Upper Ludlow Rock, 
Hagley Park, Herefordshire. 
. 10, A fragment of a large antennary joint? U. L. Ludlow. toa. Sculpture magnified. 
. 11. The basal joint of an ectognath. U. L. Ludlow. (Mr. Marston’s cabinet.) 
. 12. The serrated inner lobe of the basal joint of an ectognath (possibly of P. gigas). 
Downton Sandstone, Kington. (Mr. Banks’ cabinet.) 
13, 14. The serrated inner lobe of the basal joint of an ectognath. Fig. 13 from a 
specimen in Mr. Harley’s cabinet ; Fig. 14, from one in that of Mr. G. Cocking. 
a, the small upper tooth. 
15. A metastoma or post-oral plate. 
16. An appendage (abdominal ? or thoracic ?), much fractured ; a, the slightly mucronate 
free end; 4, the lateral striations; ¢, a serrated side lobe. (Mr. Lightbody’s 
cabinet. ) 
17, 17a. A similar side lobe, magnified. (Mr. Lightbody’s cabinet.) 
18, 19. P. punctatus. Imperfect terminal palettes of the ectognaths. (Mr. Lightbody’s 
cabinet. ) 
20, 21. P. problematicus. Anterior and posterior segments of the body. (Mr. J. 
Harley’s cabinet.) 
Figures 13 to 21 are from the Upper Ludlow Rock of Ludlow. 
Section 1.—ZRETTOPTERUS. 
. 22. Pterygotus Banksti. The carapace. From the Passage Beds, at the Ludlow Rail- 
way Station. (In Mr. Lightbody’s cabinet. ) 
. 23. The posterior segments of the body, with the telson. From the same locality and 
cabinet. 
24-26. Carapaces of different ages. Downton Sandstone, Kington. (Mr. Banks’ 
cabinet. ) 
27. Thoracic segment \ From the same formation. (Mr. Banks’ cabinet.) 
32-34. Metastoma. From the same formation. (Mr. Banks’ cabinet.) 
x, 35. The penultimate joint of an ectognath. From the same formation and cabinet. 
36-38. Telson, of young and full grown specimens. From the same formation and 
cabinet. 
. 39. Carapace of a young specimen. Upper Ludlow Rock, Ludlow. (Mr. Lightbody’s 
cabinet. ) 
. 40. A portion of an antennary chela. (40a, the same magnified.) From the same 
locality and cabinet. 
. 41. Ametastoma. From the same locality and cabinet. It is more ornamented than 
the other specimens. 
. 42. P. Banksit. The anterior half of the body, exhibiting the carapace, five thoracic 
segments, and the left ectognath. From the same locality and cabinet. 
. 43. One of the thoracic segments (second ?). From the same locality and cabinet. 
. 44. A metastoma, exhibiting a mark (indicating its point of attachment ?) ata. From 
the same locality and cabinet. 
. 45. The telson. Upper Ludlow, Whitcliffe, Ludlow. (Museum of Practical Geology.) 
. 46. The telson (of P. Banhsec ?) Batchcot, Ludlow. (Museum of Practical Geology.) 
The shape and striation are different from thoce usual in this species. 
