246 TJie American Geologist. April, 1900 
nothing yet known from that horizon. They have much 
more the appearance of fishes than the cephalaspids or the 
pteraspids; show a distinct heterocercal tail and a dorsal fin. 
They also have a row of plates or tubercles, along the ventral 
margin of which several of the hinder ones carry distinct 
spines. 
Yet more fishlike is Lasanius problematicus, of which the 
same characters have been preserved, and eighteen distinct 
scutes with sharp points are seen along the ventral surface. 
Of their position, Prof Traquair says there is no doubt, re- 
markable as it may seem. 
Summing up the results of his investigations Prof. Tra- 
quair says: "The Coelolepidse are shark-like fishes of small 
size, the largest known being only fourteen or fifteen inches 
in length. No traces have been seen of jaws, teeth, eyes, 
branchial openings, or internal skeleton." "The notion that 
the selachian spines known as Onchus. or the teeth, ^yhich 
have been named Monopleurodus and Anchistrodus, had any- 
thing to do with the Coelolepidse is entirely disposed of." 
"Nevertheless we should have no hesitation in assigning the 
latter a place among the Selachii." 
One cf the most remarkal^le and interesting forms which 
Prof. Traquair has here described is the hitherto little known 
Drepanaspis of Prof. Schluter. A series of specimens from 
Germany has enabled him to throw new light on this fossil. 
While maintaining its relation to the Coelolepidse, Prof. Tra- 
quair has, nevertheless, found it advisable to place it by itself 
in a new order, Drepanaspidse, of which it is the type. Mr. A. 
S. Woodward, in his catalogue, referred Drepanaspis to the 
coccosteids, possibly on account of the large dorsal plate 
which certainly suggests a resemblance to that of Coccosteus, 
etc. But the plate of Drepanaspis is part of the cephalic shield, 
if our author's restoration is correct, and not of the dorsal 
armour. This recalls Cephalaspis rather than Coccosteus. 
But the great head-piece of the former genus is here broken 
up into the large "central" above mentioned, two scythe- 
shaped "marginals" (whence the name), a few "rostrals" and 
a multitude of small polygonal tesselated plates which fill the 
intervening space. The tail (as restored), is heterocercal, but 
scarcelv bilobed. There is the same absence of jaws and 
