BRACHIOPODA. 



233 



The supposed Carboniferous species {Hypodema, D.K.) is, perhaps, related 

 to Pileopsis. CalceoJa is shaped like Cyrtia, and its hinge-area resembles 

 that of some Strophomenas. 



FAMILY V. Peoductid^. 

 Shell concavo-convex, with a straight hinge-line; valves rarely articu- 

 lated by teeth; closely appressed, furnished with tubular spines; ventral 

 valve convex; dorsal concave; internal surface dotted with conspicuous, 

 funnel-shaped punctures; dorsal valve with a prominent cardinal process; 

 brachial processes (?) sub-central; vascular markings lateral, broad and 

 simple ; adductor impi-essions dendritic, separated by a narrow central ridge ; 

 ventral valve with a slightly notched hinge-line ; adductor scar central, near 

 the umbo ; cardinal impressions lateral, striated. 



Fig. 153. Producta giganlea, \ Curb, limestone. 

 A, interior of dorsal valve ; B, interior of ventral valve, with the umbo removed; 

 C, ideal section of both valves ; D, hinge-line of A ; j, cardinal process; a, adductor; 

 r, cardinal muscles; b, oral processes?; s, hollows occupied by the spiral arms; v, 

 vascular impressions ; h, hinge-area. 



Producta, Sowerby. 

 Type, P. gigantea, Sby, = Anomia producta, Martin. 

 Ex. P. horrida, PI. XV. fig. 27. P. proboscidea, PI. XV. fig. 28. 

 Shell free, auriculate, beak large and rounded ; spines scattered ; hinge 

 area in each valve linear, indistinct ; no hinge-teeth ; cardinal process lobed, 

 striated ; vascular impressions simple, curved ; ventral valve deep, with two 

 rounded or sub-spiral cavities in front. These shells tnay have been attached 



M 2 



