424 APPENDIX. 



in passing over some of the earlier descriptions of sliells of this 

 group, tliat many are referred, locally, to the Holstou River, or some 

 other river. I have failed to verify these references thus far, and get 

 Goniohasis only from creeks, springs, etc. This discrepancy, as re- 

 ferring to G. glabra, Lea, renders my endeavors to identify that 

 species just enough uncertain to be always a matter of doubt. Many 

 local references to other early described species are vague and do not 

 define the station at all. Now, so far as this element goes, it is appar- 

 ently an important one in the identification or rediscovery of a species 

 or a type. As regards the group of forms to which Anthony's G. 

 arachnoidea belongs, it is spread out over a vast territory. Assuming 

 that Mr. Lea's Trypanostoma Sycamorense belongs to this tj'pe, we shall 

 find the shells ranging from the northern limits of East Tennessee, 

 along the streams that flow into the main channels of drainage down 

 to Loudon, perhaps farther. The type is pretty constant in two re- 

 markable features combined (striate-itndulatc upper whorls), though 

 sometimes the undulations become obsolete. The synonymy of this 

 type is greater than at present I dare presume to assert. 



G. porrecta, Lea, has a pretty suggestive synonymy. Mr. Lea de- 

 scribed a small shell from Claiborne, Sycamoi'e County, Tennessee, 

 that was associated with T. Sycamorense, just as we find i^orrecta with 

 arachnoidea in half a dozen places (to be icithin limits). The associa- 

 tion of species is here suggestive, as in a former case. 



As to the Trypanostomas of the creeks of East Tennessee, they are 

 a perfect series of difierentiations of carinated apices. One cannot tell 

 where to assign limits. Limits are apparently obliterated and species 

 have no existence. They are a confused mass and must be referred 

 to one type. It begins with shells that are carinate, doubly, triply 

 carinate down nearly to the last whorl, and ends with shells that have 

 a faint carina sketched on the first three or four whorls. I have not 

 the facilities for determining who is to be regarded as the patron of 

 this group. 



************ 



You remember, perhaps, my unfortunate treatment of Trypanostoma 

 curtum, Hald. You also remember that you considered the paper in 

 which it occurred of suflScient importance to honor it with a critique. 

 Interested by your suggestions, I again went over the ground covered 

 by the synonymy I suggested, only to flounder in more deeplj', and 

 finally to ascertain that one of Say's species (hitherto treated as su- 

 perfluous) was reallj^ entitled to take precedence of curtum. * * * 

 *****! am aware that where so much is uncertain scarcely 

 any one can make announcements that will be received absolutely. 

 We are very largely at the mercy of opinions, some of which, no 

 doubt, are but the reflex of the idiosyncrasies of the persons with 

 whom they originate. 



In regard to lo, I might make a few suggestions, which, when 

 carried to the extent of my investigations, would, perhaps, offer 



