FROM THE CARBONIFEROUS FORMATION. 179 



mon. As in the other types, we find a pair of legs attached to the first segment behind 

 the head and the head composed of only one segment ; such agreement in general features 

 will not permit a wide distinction, while the minor differences which do occur are certainly 

 of generic value, especially when several are correlated. 



Eileticus anthracinus, nov. sp. 

 PL 13, figs. 5, 6. 



This species is founded upon a single individual, exhibiting the lateral and partly dorsal 

 view of the anterior portion of the animal ; how much is lost posteriorly cannot be 

 positively stated, but the body is unusually stout and short, is largest from the fourth to the 

 eighth segments, and tapers toward either end, slightly in front, rapidly behind, so as rather 

 to indicate that the creature is nearly all preserved ; the body was transversely arched and 

 probably nearly cylindrical. It is 44 mm. long and 7.5 mm. broad in the widest part. The 

 head (PI. 13, fig. 5 ) is very obscure, but it can be stated to have been well rounded in front, 

 very shallow and broad ; the shortness of the head is the more remarkable from its con- 

 trast with the great length of the segments, being not one-third their length ; from the 

 upper extremity of the front projects a very obscure appendage, which is nearly 

 as long as the depth of the head, very slender, regularly tapering to a point, nearly 

 straight, slightly curved forward, and projecting upward and a little forward; it has 

 some appearance of being broken into a large number of joints. 



The segments behind the head are only eleven in number ; longitudinally they are per- 

 fectly flat, showing no sort of appearance of an anterior transverse ridge, but they are never- 

 theless composed of two nearly equal parts, a slightly larger anterior part which appears to 

 have been more chitinous, and a posterior more membranous ; these segments in the broad- 

 est part of the body are 5.5 mm. long, so that they are only half as broad again as long ; 

 their surface is entirely smooth excepting for the low mammiform tubercles which take 

 the place of the spines, and which appear to be arranged in low lateral and subdorsal rows. 

 In the lateral row there are two to each segment in the same row, one in either longitudi- 

 nal half of the segment, of which that on the anterior half appears so much more 

 prominent that it may be the base only of a real spine ; in the subdorsal rows, there are 

 three in a row on each segment and confined to the anterior half of the same ; these 

 mammiform elevations are shallow and transversely oval or roundish. 



Three or four legs are preserved at the anterior extremity, showing the diplopodous 

 character of the fossil and that the legs were long and slender ; they are apparently about 

 6 mm. long where the body is 7 mm. broad, and they are about 0.5 mm. broad in the 

 middle ; they appear to be flattened, but from their fragmentary nature no determination 

 of their jointing can be reached. They are interesting from their attachments, for one of 

 them certainly proceeds from (though it is not in absolute connection with) the anterior 

 part of the second segment behind the head, while one in front of it is similarly related to 

 the posterior portion of the first segment ; there is also something that looks like the frag- 

 ment of a leg in part of the last, and which, if so, must be a second leg to the first segment 

 behind the head. 



This specimen comes also from the Mazon Creek nodules and was communicated by 

 Prof. A. H. Worthen, of Springfield, 111. 



