264 IOWA GEOLOGICAL SURVEY 



tions which, extend obliquely downward and backward, or are 

 sometimes sigmoidally curved. The coarseness of the scale 

 ornament and that of the external bones of the head are remark- 

 able for so small sized a species. It is to be observed further 

 that the anal fin, with twenty-one rays, arises opposite the mid- 

 dle of the short dorsal. 



For an opportunity to study the type specimens, now the prop- 

 erty of the Peter Redpath Museum of McGill University, the 

 writer is indebted to the kindness of Professor F. D. Adams, 

 who collected them near Beliveau, New Brunswick, many years 

 ago. 



Formation and locality. Lower Carboniferous ; Albert county, 

 New Brunswick. 



Rhadinichthys deani, sp. nov. 

 (Plate XIII; text-figs. 40, 41 a-c) 



A moderate-sized, elaborately ornamented species, of which 

 the head has a length of from 1.4 to 1.8 cm, and is estimated to 

 have been contained from four to five times in the total length. 

 Cranial, opercular and maxillary plates ornamented with deli- 

 cate, wavy and sometimes branching and anastomosing raised 

 lines of ganoine; ornament of flank-scales consisting of fine 

 gently curved or oblique striae terminating in very delicate 

 serrations along the posterior border; a series of enlarged 

 ridge-scales extending along the middle of the back, ornamented 

 with rather coarse, wavy enamelled ridges. Flank-scales with 

 strong articular spines and sockets on inner surface. Suspen- 

 sorium very oblique, gape of mouth wide, maxillae deep and 

 strongly excavated anteriorly in the orbital region; dentition 

 in both jaws consisting of several series of different sized teeth, 

 all erect and slender-conical in shape, the larger teeth somewhat 

 widely spaced and irregularly interspersed with the smaller 

 ones. Form of body and fin-characters, with the exception of 

 the pectorals, not observed. Sensory canals of the head promi- 

 nently developed, and correlating with large size of the internal 

 auditory organs, as revealed by a number of exceptionally per- 

 fect specimens showing the brain-structure. 



