496 THE CARBONIFEROUS SYSTEM. 



belong to this species. It is distinguished from the others in having 

 all the fragments of which each segment is composed more than twice 

 as broad as long, and the upper edges of the fragments somewhat 

 raised. The segments themselves are about l-20th of an inch long, 

 slightly convex, with the anterior and posterior edges slightly and 

 equally raised at the suture. Another species, closely allied to this, 

 may be called X. similis. On different parts of the body, and even 

 in adjoining segments, the fragments composing the segments vary in 

 form from an obloirg half as long (i.e., down the segment) as broad to 

 a square ; some are even a little longer than broad. The segments 

 vary in length from l-25th to l-30th of an inch, are slightly convex, 

 and apparently have their front and hind edges turned up as in X. 

 sigillarice. To a third species I have applied the name of X.fractus : 

 here the fragments are square, the segments are not more than l-40th of 

 an inch in length, although the insect is as large as X. sigillarice; there 

 seems to be another characteristic in a distinct dorsal furrow. The 

 last species, which we may well name X. Dawsoni, is again a larger 

 one : the segments measure from l-20th to l-30th of an inch in length ; 

 one of them is depicted in Fig. 59, in the Air-breathers. These 

 segments, which are broken up into squarish or transversely oblong 

 fragments, are very differently shaped from those of the other species, 

 the posterior third being elevated into a prominent rounded ridge, 

 upon the falling slope of which the suture of the succeeding segment 

 occurs ; the anterior two-thirds of the segment is concave, with a 

 more gradual curve. 



" The second genus, Archiulus, has but a single species, which, from 

 its resemblance to the other genus, and especially to the last mentioned 

 species, may be named A. xylobioides. The segments are shaped 

 almost exactly as in X. Dawsoni, but are never broken up into frag- 

 ments ; the segments are about l-25th of an inch in length. Fig. 

 151, b, p. 385, probably refers to this species." 



Should these interesting conclusions be confirmed by Mr Scudder's 

 subsequent investigations, which he proposes to embody in a separate 

 paper, they will show that the group of Myriapods must have been 

 represented by numerous vegetable-feeding species in the Coal period 

 — a result not surprising, when we consider the vast amount of food 

 for such creatures which must have existed in the Carboniferous 

 swamps. 



