DEVONIAN FISHES OF IOWA 93 



Bothriolepis minor Newberry. 



(Text-figure 15) 



1889. Bothriolepis minor J. S. Newberry, Monogr. IT. S. Geol. Surv. 16, p. 



112, pi. 20, figs. 6-8. 

 1892. Bothriolepis minor E. D. Cope, Proc. Amer. Phil. Soc. 30, p.. 224. 

 1899. Bothriolepis minor C. R. Eastman, 17th Ann. Rept. N. Y. State Geol. p. 



324, text-fig. 5. 

 1907. Bothriolepis minor Leidy, C. R. Eastman, Mem. N. Y. State Mus. 10, 



p. 52, text-fig. 13. 



This species is readily distinguished from the preceding by its 

 smaller size and very much finer ornamentation, the external 

 surface being covered with fine, closely crowded vermiculating 

 ridges. Unfortunately, it is known only by detached plates, 

 among which the headshield and pectoral limbs are excessively 

 rare. The latter are of about the same proportions as in B. 

 nitida. Concerning the headshield it is stated by Cope that "one 

 of the characters of the species is seen in the fact that the sensory 

 grooves of the median occipital plate do not extend to the smooth 

 articular border, but are separated from it by a band of sculp- 

 ture. The premedian plate is crossed by a groove which pre- 

 sents an abrupt loop backwards at the middle. ' ' 



As is commonly the case with this class of remains, the antero- 

 dorso-median plate is of much more frequent occurrence than 

 any other, though seldom found entire. Its orientation may 

 be easily determined by means of the V-shaped sensory canals 

 which diverge from about the center of the plate, or, in case the 



Fig. 15 

 Fig. 15. Bothriolepis minor Newb. Antero-dorso-median with denuded, ^'superficial 

 ornament. Catskill, Delaware county, New York. xl-1. 



