TBIGONIA.— Plate I. 



moderately convex, but little angled posteriorly, ribs 

 less prominent, distant, nodules rather small. 

 Lamarck, Ann. du Mus. vol. iv. p. 355. pi. 67. f. 2. 



Trigonia pectinata, Lamarck. 

 Hab. Tasmania. 



This is the largest of the recent Trigonia, a native of the 

 shores of Tasmania, and it is distinguished by a more or- 

 bicular form, while the ribs are not so strongly developed. 



Species 4. (Mus. Cuming.) 

 Trigonia Strangei. Trig, testa subobtuse rotundatd, 



postice sttbabbreviato-angulatd, coslis amplis, coufe>iis, 

 Tiodis numeromsimis, compimte verrucatis. 



Strange's Trigonia. Shell somewhat obtusely rounded, 

 posteriorly rather shortly angled, ribs large, close- 

 set, with the nodules very numerous and conspicu- 

 ously warty. 



Adams, Pro. Zool. Soc. 1852, p. &1. 



Hab. Sydney, New South Wales (in deep water); Strange. 



A very characteristic species, distinguished at once 

 from all the rest by its crowded wart-like nodules. 



