CLAVELLATiE. 33 



Trigonia tuberculosa, Lye. Plate V, figs. 9, 10. 



Trigonia tuberculosa, Lycett. Ann. and Mag. Nat. Hist., 1850, pi. xi, f. 9. 



— — Morris. Catal., 1854, p. 228. 



— — Lycett. Cotteswold Hills Handbook, 1857, pi. iii, f. 4. 



— clavellata, Quenstedt. Der Jura., 1857, t. 60, f. 14 ?. 



— tuberculosa, Rigaux and Sauvage. Descr. deesp. nouv. de L'Etage Bathon 



du Bas-Boulonnois, 1868, p. 19. 



Shell ovately trigonal, depressed ; umbones small, mesial, and recurved ; anterior 

 border produced, curved elliptically with the lower border ; superior border sloping and 

 nearly straight ; area narrow, with two small delicately tuberculated bounding carinas, 

 traversed transversely by plain costellse, which become posteally somewhat rugose and 

 less conspicuous. The sides of the valves have a numerous series (from eighteen to 

 twenty) of rows of curved and delicately tuberculated costse. The tubercles are regular, 

 very closely arranged, slightly compressed laterally, obtuse and produced downwards, so 

 that their bases almost touch the next succeeding row ; they are of equal size, excepting 

 near to the carina, when the rows become smaller. 



It is allied to T. Grieshachi, Lye, to which the reader is referred, and also to T. clavulosa, 

 Rigaux, and Sauvage, Mem. de la Soc. Acad, de Boulogne, 1867, vol. 3. The latter 

 species appears to differ from it solely in having delicate transverse striations upon the 

 area in lieu of the costellae upon our T. tuberculosa. 



Geological position and locality. The Inferior Oolite shelly freestone at Leckhampton 

 Hill, near Cheltenham, where it has occurred rarely. Specimens are in the National 

 Museum, Jermyn Street, in the cabinet of Dr. Wright, of Cheltenham, and of the Rev. 

 P. B. Brodie, of Rowington ; for the smaller specimen figured I am indebted to the 

 kindness of the latter gentleman. Our figures do not clearly show the downward 

 prolongation of the little tubercles in each row. 



Trigonia imbricata, Sow. Plate VI, fig. 5 a, b. 



Trigonia imbricata, Sowerby. Mineral Conchology, 1826, t. 507, figs. 2, 3. 



— Morris and Lycett. Gr. Ool. Monog. Pal. Soc, 1853, p. 63, 



t. 6, figs. 8, 8a. 



— — Morris. Catal., 1854, p. 228. 



— — Oppel. Juraformation, 1857, p. 485. 



Under the above name Mr. Sowerby figured a minute Trigonia, which appears to be 

 in an immature or young condition, and of which adult specimens have not been recog- 



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