NATURAL SCIENCES OF PHILADELPHIA. 113 



Trypanostoma validum ? Anthony. 1 



Loc. 5. 

 Trypanostoma fastigiatum ? Anthony. 1 



Loc. 20. The three supposed species above named seem to form 

 a natural group with T. parvum, Lea, and like that species they 

 are found associated with shells which seem to be a variety of An- 

 culosa subglobosa, Say. It is possible some future writer may 

 unite them as one species. 



Trypanostoma, (N. S.) Lea. 



Localities, 7, 18. 

 Trypanostoma attenuatum, Lea. 



Localities, 41, 32. A variable species, which some of my cor- 

 respondents call T. strigosum, Lea. 



Trypanostoma unciale, Hald. 



Localities, 1, 3, 5, 8, IT, 32. The species is defined as striate or 

 carinate above. I have separated from it all plicate-striate shells 

 that have been referred to this species by my correspondents. 

 The largest shells occur in loc. 8 ; they are also variable, some of 

 them passing through phases referable to the next species to forms 

 entirely free from striations and carinas. The most perfect forms 

 occur in loc. 1*7. 



Trypanostoma Estabrookii, Lea. 



Localities, 2, 4, 8, 16, 18. The shells of loc. 18 are very fine, 

 perfect, and slender ; and have been referred by a correspondent 

 to T. unciale. The shells of loc. 16 are small and imperfect. 



Goniobasis arachnoidea, Anthony. 



Localities, 1, 2, 3, 4, 6, 9, 10, 13, IT, 18, 19, 21, 23, 25, 27, 28, 29, 

 35, 36, 37, 43. The local varieties are very perplexing, and some 

 of them could not have been identified but for the aid derived from 

 shells of other localities. Some of the various forms have been 

 referred to Try. unciale ; others to Gon.baculum; some of the 

 more slender varieties have been referred to Gon. carinifera, Lam. 

 The shells of one locality (23) have been called an undescribed 

 species of Trypanostoma. Of two other localities (28, 43) the 

 shells have been supposed to be another undescribed species of 

 Trypanostoma. These shells bear a strong resemblance to Mr. 



1 According to Mr. Wheatley. 



