Cope.] ^^4 [-April 1, 



fragment. From this point forward they diverge in a direction gradually- 

 approaching and thus reaching a right angle with the margin. The 

 transverse grooves form a band which increases in width anteriorly until 

 it is nearly one-third the width of the plate in front. The grooves are 

 fine and are separated by interspaces wider than themselves. Tliey be- 

 come coarser anteriorly, the interspaces measuring 1.5 mm. ; posteriorly 

 they measure 1 mm. 



The middle line above shows some unsymmetrical low tuberosities 

 which do not correspond to cavities on the inferior side. The plate is 

 generally thin. 



Measurements. 



MM. 



Length of fragment 222 



"Width of plate at front of fragment 110 



Thickness of plate at front of fragment 5 



Width of plate at posterior border 120 



This piece, together with the pectoral limb which I have already de- 

 scribed, demonstrates the position of the genus to be with the Antiarcha, 

 and not with the Arthrodira, as has been suspected by Mr. A. S. Wood- 

 ward. 



Chemung, Bradford county, Pa., A. T. Lilley. 



BOTHRIOLEPIS MINOR Ncwb. 



Paleozoic Fishes of North America, 1889, p. 113 ; PI. xx. Figs. 6-8. 



Fragments of this species are exceedingly abundant in the Chemung 

 rocks in Bradford county, but generally dissociated. The examination 

 of a large number of these demonstrates the correctness of the generic 

 references made by Prof. Newberry. The most abundant pieces are 

 the lateral ventral plates, the anterior median dorsal plate, and the median 

 occipital. The latter sometimes remains in conjunction with the plates 

 on either side of it. 



These specimens are unaccompanied by any trace of scales or fins, thus 

 agreeing with other species of the genus. There is also but one median 

 abdominal plate, showing that the B. minor is not to be referred to Holo- 

 nema. One of the characters of the species is seen in the fact that the sen- 

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

 articular border, but are separated from it by a band of sculpture. The 

 preraedian plate is crossed by a groove which presents an abrupt loop back- 

 wards at the middle. The species always remains much smaller than the 

 B. nitidus Leidy (j5. Uidyi Newb.). 



Leroy, Bradford county. Pa., A. T. Lilley. 



