106 JURASSIC RHYNCHONELLIDS 
very strong, sharply angular ribs which arise from the umbones and continue simply 
to the anterior margin. Concentric ornament, not always preserved, consists of 
numerous fine growth lines, together with occasional coarser growth lamellae. 
The species has a characteristically strong, high, suberect beak which is flanked by 
a large, well-marked interarea, although the beak ridges limiting these are only 
weakly developed. TJ. speciosa possesses a large hypothyridid pedicle opening. 
DIMENSIONS OF FIGURED SPECIMENS. 
length thickness width 
5°50 cm 6-87 cm 
4°73 cm 5:00 cm 
5:4 mg ZA 
6:0 6:5 
Fic. 37. Transverse serial sections of Torquirhynchia speciosa (Munster). Kimmeridgian/ 
Lower Volgian. ‘“‘ Dicevas Kalk’’. Saal, Germany. (3). 
Internal characters. Pedicle valve. There is a weakly developed pedicle collar. 
The deltidial plates project slightly, ‘“‘ reinforcing ’’ the pedicle opening ; below the 
level of the pedicle opening they become conjunct and then “ crumple up ”’ against 
one another. Relatively slender, subparallel dental lamellae are present. The 
teeth are strong and crenulated ; there are well developed lateral denticulae. 
