228 THE DEVONIAN OF MISSOURI. 



Family Cystodictyonidae 

 Genus Cystodictya Ulrich 



Cystodictya cf. rigida (Hall) 



Plate 60, figures 6, 7 



1881. Stictopora rigida Hall, Trans. Albany Inst., vol. 10, abstract, p. 14. 

 1883. Stictopora rigida Hall, Report of State Geologist for 1882, Expl. 25, figs. 15, 16. 

 1887. Stictopora rigida Hall and Simpson, Nat. Hist. N. Y. Pal., vol. 6, p. 91, pi. 28, 

 figs. 15, 16. 



Description — Zoarium consisting of a flattened stipe, with straight, bifurcating 

 branches; width of branches about 4 mm., just below bifurcation width increases to 

 5mm. Cell apertures oval, length about .30 mm., width about half as great. When split 

 longitudinally and parallel to zoecial surface, the specimens show the mesathecal sur- 

 face which is marked by sub-parallel, angular, and slightly undulating, longitudinal 

 ridges. ' 



Remarks — A single specimen showing the mesathecal surface has been observed, 

 which resembles this Onondagan species. It differs in having somewhat wider branches, 

 and in having transverse ridges not shown on specimens figured by Hall. 



Horizon — Upper beds. 



Figured specimen No. 27661 Walker Museum. 



MOLLUSCOIDEA 



Class BRACHIOPODA 

 Order Neotremata 

 Superfamily Craniacea 



Family Craniidae 



Genus Pholidops Hall 



Pholidops ovata Hall 



Plate 61, figures 1, 2 



1859. Pholidops ovatus Hall, Nat. Hist. N. Y. Pal., vol. 3, p. 490, pi. 103, b, fig. 7. 

 1903. Pholidops ovatus Weller, Geol. Surv. N. J. Pal., vol. 3, pi. 226, pi. 20, figs. 27-29, 



p. 300. 

 1913. Pholidops ovata Schuchert, Geol. Surv. Md. Low. Dev., p. 294, pi. 53, figs. 10-12. 



Description — Shell small, circular to ovate. The dimensions of a pedicle valve are: 

 length 2.5 mm., width 2 mm. Apex excentric. The fine concentric lamellae common 

 to this species have not been noticed in the specimens which have come under my 

 observation. An impression of the pedicle valve shows the well defined anterior muscle 

 markings which extend nearly to the middle of the shell. 



Remarks — This little form of attached brachiopod is represented by three dorsal 

 valves only, and there appears to be no essential variation from the New York speci- 

 mens. 



Horizon — Lower beds. 



Figured specimens No. 27Jf83 Walker Museum. 



