5Gi Systematic Paleontology — IJprER Devonian 



tinii. 'J'lio development of these cliaracters is insuiEoient to bring the 

 shell into close association with the productoid genera, Produdella and 

 I'lodndus. It is much to he regretted that other representatives of this 

 interesting shell have not been observed. 



J^ength G mm.; width 10 mm. 



Occurrence. — Jexxings Fok.matiox, I'aukiikad ^Membicu. ^lillstoiie. 



Collection. — ]\Iarvlaiul Geological Survey. 



Genus PRODUCTELLA H.ill 

 Pkoductella lachkymosa (Conrad) 



Plate L, Figs. 20-22; Plate LI, Figs. 1-3 



Strophomena laclirpmosa Conrad, 1S42, Jour. Acad. Nat. Sci., Phila., voL 



viii, p. 25(), pL xi, fig. 9. 

 Productella lachrymosa Hall, 18G7, Paleontology of New York, vol. iv, p. 172, 



pi. XXV, figs. 23-28. 



Description. — Shells sul)licmisplu'ric. stil)elli|)tical in marginal outliiiL'; 

 hinge-line equalling or shorter tliaii the width of the valves. Yenti'al 

 valve convex or ventricose, often medially depressed. Surface closely 

 spinous, the spine bases being elongate and arranged with some regularity 

 in concentric rows, depressed lateral slopes with more erect spines. 

 Dorsal valve concave. Sharp internal casts show admirably the narrow 

 cardinal area in Imtii ventral and dorsal valves, and the matri.x of the 

 specimens contains spines a half-inch in length. The interior of dorsal 

 valve shows but faint trace of median septum and the cardinal process 

 is erect, thin and bifurcate at its crest. The expression of some of the 

 shells whicli are medially depressed and somewhat extended transversely 

 is that of the New York variety Unia Hall, but it is iiupractical)le here 

 to differentiate these from the associated shells. 



Length 22 mm.; width 27 mm. 



This species is subject to wide variation. It differs from /'. speciosu 

 in its lai'ge inflated umbo and in possessing fewer spines, which are at- 

 1ach"il hv cldiigatcd bases. This form is abuiidanl in the L'ai'khcad. and 

 somewhat less abundant in the Chemung of Maryland. 



Occurrence. — -Texxings Fokm.vtiox, Chemux'g Member. Oakland- 

 lli'ilhiuise Poad; Trout Pun; National Poad, on Polish Mountain near 



