152 S. H. SCUDDER ON RPINED MYRIAPODS 



appearance of being the termination of the body, and an appendage, presumably an antenna 

 or a part of one, is attached at the upper margin of the front ; it would also be in keeping 

 with the general form of these animals as shown by the study of all the species if this 

 anterior segment were the head. 



This head segment is only about half the size of one of the nearer body segments, round- 

 ed, higher than long, the front rather flattened, and bearing in front, above, a straight 

 antenna composed apparently of three joints, the basal joint equal, small, cylindrical, slen- 

 der, longer than broad, the apical oblong ovate, twice as broad as the others and four or 

 five times longer than broad ; the whole antenna is 6 mm. long, of which two thirds belongs 

 to the apical joint, whose greatest diameter is 0.9 mm. From the lower outer angle of 

 the head projects a bundle of spines (?), which afterwards diverge into three nearly straight 

 rods ; they evidently do not belong where they are, but their structure and surface appear- 

 ance give them the aspect of spines and not of legs ; the triangular offshoot from them 

 appears to have no connection with them, but to be an accidental mark in the stone. 



The segments of the body behind the head £ire forty in number, and of a similar size ; 

 where the body is broadest the length of the segment is 5.5 mm., and this proportion of 

 length to breadth holds tolerably well throughout, the segments being about three times as' 

 broad as long. They appear to be strongly arched and more equally than would appear to be 

 the case in the next specimen to be described, although some segments seem to present an 

 anterior, broad, rounded side where the spines are seated ; certainly the segments are 

 deeply and coarsely incised. A large part of the body and of the spines (PI. 11, fig. 8) are 

 covered with circular flattened raised disks of a yellowish color (PI. 11, fig. 7), with a 

 slightly raised rim and either a depression or a slight elevation at the centre, crowded 

 closely together and appearing as if formed of the dried up contents of the body ; the outside 

 of the spines seem to show them quite as much as the inside of the same ; indeed the 

 outside of the spines appears to be entirely made up of them. They are usually about 

 0.5 mm. in diameter, but a considerable number are smaller and show no structure ; the 

 head, antenna and the trifid appendage of the head are all furnished abundantly with them, 

 but they are entirely absent from the legs. 



The only spines that are preserved belong, apparently all of them, to the subdorsal row, 

 but the openings into the hollow interiors of those which are necessarily concealed indicate 

 clearly that there are three rows upon either side, arranged exactly as described in the 

 specimen figured by Messrs. Meek and Worthen. The spines of the subdorsal rows (PI. 11, 

 fig. 8) are cylindrical, equal, hollow throughout, rather longer than the diameter of the body, 

 rather deeply and equally forked at tip, so as to appear Y-shaped, the branches not very 

 divergent; at the base, (in the anterior part of the body), or near the same (in the pos- 

 terior part of the body), is at least a pair, but more probably a whorl, of subsidiary spines 

 springing from the main stem ; anterior and posterior spinules are preserved at the base of 

 nearly all the spines, but there are also indications of others which lie interiorly and 'exte- 

 riorly, and which necessarily cannot be very clearly exhibited in a fossil like this ; such an 

 indication appears at the base of PI. 11, fig. 8, representing the spine enlarged, where a 

 rounded hollow seems to prove a spinule in addition to those in front and behind, as clearly 

 as the other pits in the body walls indicate the position of the principal spines ; they appear 

 to originate at the very base of the spine throughout the body and to be less divergent 



