FISHES OF THE CARBONIFEROUS SYSTEM. 205 
Mr. O. St. John! unites Sandalodus crassus with S. spatulatus, N. & W.,? 
but a large number of specimens of S. crassus which I have received from 
Alton, Saint Louis, and Greencastle, conform closely with the type now 
figured, and among them all I find none which correspond with that from 
which the description of S. spatuwatus was taken. Mr. St. John considers 
that as simply a much-worn tooth, but the wear of these crushing teeth 
came only on higher portions of the crown. Of this a good illustration is 
given in the specimen represented in Fig. 8, a normal tooth of S. crassus, but 
having all the more elevated portion worn away by use. The margins are 
complete and the enameled surface intact and polished, except in the central 
part, which bore the brunt of the attrition to which the tooth was subjected. 
In this specimen we see nothing of the beveled border or the projecting 
point which shows so plainly in Fig. 6, but that is due to the fact that here 
the enameled crown is separated from the bony base. 
Oropus RAmosus, Ag. 
Plate XXVII, Fig. 29. 
Orodus multicarinatus ?, N. & W.; Geol. Survey Illinois, vol. 2, p. 62, pl. 4, fig. 13. 
To the courtesy of Dr. Charles Rominger, former State geologist of 
Michigan, I am indebted for the beautiful tooth now figured _ It is repre- 
sented of the natural size; is four and a half inches long by thirteen lines 
wide at the center; it shows the entire form of the crown and all the details 
of the surface markings. The general shape is similar to that of most of the 
large teeth of Orodus; i. e., it is broadest and highest near the middle, nar- 
rowing to either side, somewhat bent in outline. The crown is covered 
with a series of sharp, flexuous, and somewhat pectinated carinze, of which 
the most conspicuous traverses the surface from end to end, but eccentrically. 
From this ridge (longitudinal as regards the tooth, transverse with reference 
to the mouth of the fish) descend to the margins at frequent intervals 
equally strong, sharp, simple, or forked pectinated branches These cover 
all the crown surface, but less closely on the subcentral cone, which is broad 
and prominent. The enameled surface is obscurely punctate throughout. 
1 Geol. Survey Illinois, vol. 7, p. 188. 2Tbid., vol. 2, p. 103, pl. 10, fig. 2, 
