46 BRITISH FOSSIL TRIGONLE. 



direction and more close arrangement. The tubercles are also smaller and much 

 more numerous. The three smaller immature examples are from the Coralline Oolite of 

 Wiltshire. A specimen larger than these latter, but also of immature growth, was for- 

 warded by Professor Grewingk, of Dorpat, to Mr. Leckenby, together with a series of 

 Livonian Oxfordian testacea. The Trigonia was named T. clavellata, var. Jurensis, 

 obtained in the vicinity of Popilacny, Province of Kowno, associated with a young example 

 of T. monilifera, Ag. Prance, Tonnere (Yonne). 



Trigonia parcinoda, Lycett, sp. nov. 



Shell small, moderately convex, ovately subquadrate, the length slightly exceeding the 

 height ; umbones small, antero-mesial ; area large, flattened, or slightly concave, tra- 

 versed transversely by large regular costellse ; there is no mesial furrow ; the marginal 

 carina is small but distinct ; its sub-umbonal portion has several minute tubercles, there is 

 no distinct inner carina and the escutcheon is small and inconspicuous ; the posteal 

 border of the area descends abruptly from the extremity of the 

 escutcheon. The other portion of the surface has about ten rows of 

 small horizontal and gently curved costse, each of which is crossed 

 perpendicularly by about six small regular varices ; these are of moderate 

 size and are distantly arranged about the middle of the valve, becoming 

 Magnified twice. small and indistinct towards the anteal border ; the costellae upon the 

 area form continuations of the costse, but near to the posterior border the former become 

 smaller and more numerous. 



Height, 4 lines ; length, 5 lines ; the surface of the area is equal to two fifths of the 

 entire valve. 



A pretty little sub-quadrate species remarkable for the few small, widely separated 

 perpendicular varices upon the costated portion of the valves ; it does not possess any 

 striking affinities to other of the Clavellata, and is known only by the sole specimen here 

 figured, which is now in the British Museum, numbered 67,272. 



Stratiyraphical position and locality. It was collected many years since by Mr. 

 Etheridge in the Inferior Oolite of the Halfway House Quarry near Yeovil. 



Trigonia impressa, Sow. Plate VII, figs. 4, 5. 



Trigonia impressa, Sowerby. Jour. Zool., vol. 3, tab. xi. 



— — Prevost. Ann. Scient. Nat., vol. 4, tab. xviii, figs. 22, 23. 



— — Morris and Lycett. Pal. Soc, 1853, p. 61, tab. v, fig. 14. 



— — Morris. Catal., 1854, p. 228. 



— — Lycett. Cotteswold Hills Handbook, 1857, pi. vii, fig. 5. 



