SOME NEW DEVONIC FOSSILS 



247 



stands to Rensselaeria (R. ovoides) in the relation of a neanic 

 to an ephebic condition. R. a 1 1 a n t i c a , in its progressed 

 expression even though retaining the primitive structure of the 

 cardinal areas, can not be brought within that group, and Trigeria 

 can not be construed as a valid generic term in the face of the 

 facts here adduced. 



In the closest association with the Edmunds Hill and Dalhousie 

 shells are specimens which I have received from Prof. E. Kayser 

 labeled R. strigiceps Roem. from the Siegen greywacke, at 

 Siegen (Coblentzian). Though the shell is persistently smaller 

 than those referred to, it is of the same contour, degree of plication 

 and interior structure, emphasizing again the " Trigeria " char- 

 acters. Precisely what is the relation of this small form from 

 Siegen to the large, elongate, more characteristic examples of 

 R. strigiceps from the Taunus quartzite at various locali- 

 ties which bears so strong a resemblance to R. atlantica, the 

 writer is not in position to say, but it may prove to be the same 

 as that we have here indicated. 



Rensselaeria (Amphigenia) parva no v. 



A small, sometimes quite elongate species often presenting the 

 appearance of a miniature of A. elongata Conrad. In the 



Rensselaeria (Amphigenia) parva 



ventral valve the median septum is strong and the spondylium well 

 developed, the lateral surfaces of the bottom of the valve vascular 



