128 THE DEVONIAN OF MISSOURI. 



1908. Dinichthys pustulosus Eastman, Iowa Geol. Surv., vol. XVIII, pp. 194-198, 

 pi. 1, fig. 10; pi. 4, text-fig. 28. 



Eastman's description — "A primitive species seldom exceeding and usually some- 

 what smaller in size than D. intermedins, distinguished from it and its contemporaries 

 in the Ohio Upper Devonian by its fine tuberculation, undulating suture lines, and 

 decidedly Coccosteus-like aspect. Lower dental plates with a simple trenchant margin 

 terminating behind in an abrupt downward declivity bearing a series of few, regularly 

 spaced rudimentary denticles. Palatopterygoid dental plates ("shear-teeth") with 

 convex functional margin, simply trenchant, and not denticulated along the posterior 

 border, so far as known. Vomerine teeth resemble those of D. intermedins. Visceral 

 surface of occipital region without prominent ridges, and posterior pit on under side of 

 the median occipital scarcely divided. Pineal plate apparently in contact with the 

 centrals, and with inconspicuous foramen." 



Remarks — -Only fragments have been collected from the Devonian of Missouri 

 and their identification is not certain. Two median occipitals, one rostral, and two 

 antero-dorso-laterals are all the specimens collected excepting fragments. The bones 

 are smaller than those previously figured. The median occipital is narrower in front than 

 in the type. 



Occurrence — Mineola limestone of Ralls County. 



Family Pterichthidae 

 Genus Glyptaspis Eastman 



Glyptaspis 



Plate 31, figure 3 



Part of a large plate with the type of marking peculiar to the ventral plates of 

 Glyptaspis was collected from the Snyder Creek shale of Callaway County. The figured 

 part seems to represent not more than half of the original plate. The broken edge 

 opposite the preserved margin is 1 cm. thick, and the broken ends are nearly as thick. 

 Several times the writer has collected fragments of plates with ornamentation like 

 that figured, but this is the only specimen which in any way indicates the shape. The 

 preserved edge is thin and sharp. 



Order Ctenodipterini 



Family Ctenodontidae 



Genus Dipterus Sedgewick and Murchison 



Dipterus mordax Eastman 



Plate 21, figure 11 



1900. Dipterus mordax Eastman, Jour, of Geol., VIII, pp. 39-40, text-figs. 6, 8. 

 1908. Dipterus mordax Eastman, Rept. N. Y. State Mus., LX, pp. 161-162, pi. 4, figs. 



5 and 6. 

 1908. Dipterus mordax Eastman, Iowa Geol. Surv., XVIII, pp. 220-221, pi] 2, figs. 

 4 and 5; pi. 7, figs. 5-9. 

 Eastman's description — "Lower dental plates attaining a length of over 3 cm. 

 coronal surface gently convex, with six rows of very large, discrete, conical or rounded 

 tubercles which extend from the outer margin for a variable distance toward the pos- 

 terior angle; the two posterior rows often rudimentary. Some of the tubercles, when 

 worn by use or by post-mortem abrasion, become elongated in the direction. The 

 coarseness of tuberculation, in proportion to the size of the plates, is greater than in 



