78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



can consider them to be the same as the form described by de Ver- 

 neuil and Barrande [i860, p. 536], 



From M. Barrande's description and illustration, the following 

 note is written : The shell is about as wide as long, suboval, with 

 pointed beaks; valves moderately convex, with the ventral a little 

 more so than the dorsal. There is a small area on each valve, but 

 no trace of a triangular false deltidium. Beak of ventral valve with 

 a minute pedicle opening. Surface with fine, distinct, concentric 

 striae. Substance of shell calcareous. 



A shell 13 mm. in length has the same width, and the thickness 

 of the two valves united is 5 mm. 



M. Barrande thought that a new genus was indicated, but in the 

 absence of interior characters decided not to name the genus or 

 species. The perforate ventral valve and area suggested Siphono- 

 treta to him, but the calcareous shell was opposed to it. 

 • I have provisionally referred the shell to the genus Botsfordia 

 and have named it after M. Barrande, whose memory all paleon- 

 tologists take pleasure in recalling. 



The reference to Botsfordia is made on account of (a) the sub- 

 acuminate ventral valve with minute pedicle opening above a listrium 

 unmarked by a false deltidium ; (b) convex ventral and dorsal valve ; 

 (c) the tendency of Botsfordia pulchra (Matthew) [1889, p. 306] 

 to have the substance of its rather thick shell replaced by calcareous 

 matter. 



I have attempted to secure specimens of this shell, but unsuccess- 

 fully. Until further information can be secured, the present refer- 

 ence will serve to indicate the probable relationship of the species. 



Formation and Locality. — Middle Cambrian: Red limestone 

 which passes north of Adrados and Boiiar, near Sabero, Cantabrique 

 Range, Province of Leon, Spain. 



DEARBORNIA, new genus 



This genus is based on one species, which is well represented by 

 fourteen specimens. The generic description is incorporated with 

 the description of the type species. 



Type. — Dearbornia clarki, new species. 



DEARBORNIA CLARKI, new species 



Plate 8, Figure 7 



Shell subequivalve, subcircular in outline, slightly convex. Ven- 

 tral valve most elevated at the pedicle aperture, which is circular, 

 rather large, and situated from one-fifth to one-sixth the length of 



