Vol. 70.] DEYELOPilEXT OF TRAGOPHYLLOCERAS LOSCOMBI, 341 



Fig. 1. — Development of the suture-line of Tragophylloceras 

 loscoiiibi («7. Sowerby). 



[a, b, & c, representing the first, second, and seventh sutures, belong- to a 

 specimen (No. 1575, Coll. Lang) from 10 feet above the Belemnite- 

 Stone ; d-l (No. 919, Coll. Lang) come from 14 feet above it ; and m 

 (No. 1201, Coll. Lang) again from 10 feet above the Belemnite-Stone, 

 all from Black Ven. The numerals indicate the diameters in milli- 

 metres.] 



