PLATE 13 
All specimens coated and magnified x 31.5 
Fics. 1-3. Taphrognathus — Cavusgnathus transitions 
1. Oral view of specimen X 558. 2. Oral view of specimen X 559. 3a. Oral view of specimen 
X 560. 3b. Aboral view of specimen X 560. 3c. Outer lateral view of specimen X 560. 
Fics. 4,5. Taphrognathus varians Branson & Mehl 
4a. Oral view of specimen X 407. 4b. Aboral view of specimen X 407. 4c. Outer lateral 
view of specimen X 407. 4d. Inner lateral view of specimen X 407. 5a. Oral view of specimen 
X 408. 5b. Aboral view of specimen X 408. 5c. Outer lateral view of specimen X 408. 
5d. Inner lateral view of specimen X 408. 
Fics. 6, 7, 13. Cavusgnathus charactus Rexroad 
6a. Oral view of specimen X 59. 6b. Aboral view of specimen X 59. 6c. Outer lateral view 
of specimen X 59. 6d. Inner lateral view of specimen X 59. 7a. Oral view of specimen X 61. 
7b. Aboral view of specimen X 61. 7c. Outer lateral view of specimen X 61. 7d. Inner lateral 
view of specimen X 61. 13a. Oral view of specimen X 62. 13b. Aboral view of specimen 
X 62. 13c. Inner lateral view of specimen X 62. 
Fics. 8-11. Polygnathus bischoffi sp. nov. 
8a. Oral view of hypotype X 352. 8b. Aboral view of hypotype X 352. 8c. Lateral view of 
hypotype X 352. ga. Oral view of paratype X 351. 9b. Aboral view of paratype X 351. 
gc. Lateral view of paratype X 351. 10a. Oral view of paratype X 350. t1ob. Aboral view 
of paratype X 350. toc. Lateral view of paratype X 350. 11a. Oral view of holotype X 349. 
11b. Aboral view of holotype X 349. 11c. Lateral view of holotype X 349. 
Fic. 12. Cavusgnathus naviculus (Hinde) 
a. Oral view of specimen X 65. b. Outer lateral view of specimen X 65. c. Aboral view of 
specimen X 65. d. Inner lateral view of specimen X 65. 
