662 PROCEEDINGS OF THE ACADEMY OF [Dec, 



Considering, now, the specimen dealt with in this paper, we find that 

 the interlateral shows no positive evidence of fusion with any other 

 bone and seems to agree with the condition met with in Coccosteus 

 decipiens. Further, it may be stated that its posterior margin looks 

 as if it might have carried the thin blade found in D. intermedins, 

 but the condition of preservation hardly warrants a final decision on 

 this point. 



If, now, we examine the plate which was at first believed to be a 

 suborbital, we find that it is apparently onby a part of a larger bone, 

 the fragments of which lie (in the figure) to the left of the big mass. 

 When a reconstruction of this bone is attempted, its outline is, in a 

 general way, quite similar to that made by the combined antero- and 

 posterolaterals of Coccosteus or the broadly expanded upper portion 

 of the "clavicular" in Dinichthys. The author offers the suggestion, 

 therefore, that this bone probably represents a lateral plate of some 

 kind. In support of this suggestion it may be said that the bone in 

 question occupies just such a position as that in which we might 

 expect to find a lateral plate when the entire abdominal armor is so 

 crushed that the dorsal and ventral plates are brought into the same 

 plane. According to this hypothesis, the plate was not only brought 

 into the horizontal plane, but also rotated forward through an angle 

 of about ninety degrees. The same pressure pushed the left antero- 

 dorsolateral backward while it turned over with its outer side exposed. 

 The right antero-dorsolateral in coming to rest in the same plane with 

 the others was pushed far forward of its natural position. 



Though realizing that any conclusions in regard to the strictly 

 lateral armoring which ma}- be based upon this specimen are only 

 tentative, the author believes that he may safely express the opinion 

 that the interlateral in this Marcellus Dinichthyid occupies practically 

 its normal position, that in this respect it agrees with Coccosteus, and 

 that it offers a clue which may be of importance in properly orienting 

 the "clavicular" (be it one element or two) in the higher Dinichthyids. 

 Acanthodian Remains from the Marcellus Shale. — These remains 

 of Acanthodians are quite fragmentary, but the extreme rarity of the 

 members of this order in the Paleozoic strata of North America render 

 advisable a short description of these two Middle Devonian specimens. 

 ( )ne specimen collected by the writer came from the Marcellus shale 

 of the Kimber Springs Ravine, southwest of Onondaga Valley, N. Y. 

 It comprises but a single spine less than 15 mm. in length. The 

 proximal portion is imperfect, but clistally it tapers off in a graceful 

 curve to the nearly complete point. Three longitudinal grooves and 

 ridges are plainly visible. 



