284 S. IT. SCUDDER ON NEW TYPES 



ventral fields. It is also supported by a vague appearance of what seem to be legs on one 

 or two of tlic specimens, and which show two pairs to each dorsal segment. The close 

 general gesemblance of most of the species to the species of Euphoberia is also an argu- 

 ment in favor of the same supposition; and would, perhaps, by itself , be considered suffi- 

 cient to one studying these forms, were it not for the unexpected discovery of Ti very 

 distinct type of chilopodiform myriapods next to be considered. 



This second type, as we have remarked, has been known to naturalists for some time 

 under the name of Palaeocampa, given to it by Messrs. Meek and Worthen in 18G5, under 

 the supposition that it was a caterpillar. The original specimen, figured in 1866, was de- 

 stroyed by lire a year or two later, but a better specimen enabled these naturalists to give 

 further description of the spines in the same year that I questioned the lepidopterous 

 nature of the fossil ; and to express the opinion, that, as 1 had suggested from the figure alone, 

 " it was more probably a worm." 1 have now received, through the favor of Messrs. Carr 

 and Bliss, three remarkably well preserved specimens of what is undoubtedly the same 

 creature, and which show that the animal combined some most extraordinary features. 

 One of these specimens, the djscovery of Mr. Bliss, shows the legs distinctly on both halves 

 of the split nodule in which it occurs, and gives one much fuller information concerning 

 this ancient creature than one could gain from the legless specimens otherwise known. 



But for my previous study of the Archipolypoda of Mazon Creek, and the revelation 

 which these ancient types give of the divei-gence of structure between extinct and mod- 

 ern forms of Myriapoda, it would have been difficult to reach the full conviction that 

 Palaeocampa was a myriapod. It is a caterpillar-like, segmented creature, three or four 

 centimeters long (pi. 26), composed of ten similar and equal segments besides a small head; 

 each of the segments excepting the head bears a single pair of stout, clumsy, subfusiform, 

 bluntly pointed legs, as long as the width of the body, and apparently composed of several 

 equal joints. Each segment also bears four cylindrical but spreading hunches of very 

 densely packed, stiff, slender, bluntly tipped, rod-like spines a little longer than the legs. 

 The bunches are seated on mammillae and arranged in dorsopleural and lateral rows. 



The individual rods have an intricate structure (pi. 2d. figs. 1-4); instead of being striate, 

 as supposed by Meek and Worthen in their last examination, they are furnished externally 

 with about eighteen longitudinal, equidistant ridges, about half as high as their distance 

 apart; the edges of these ridges are broken into slight serrations at regular intervals about 

 equal to the distance between neighboring ridges, the highest point of each serration 

 being toward the apex of the spine; the body of the ridge itself appears as if broken at 

 each serration. The intervening space between neighboring ridges is equally divided by 

 two or three exactly similar, but miniature ridges, serrated at more frequent intervals. 

 This serration of both larger and smaller ridges, with the apparent jointing or incision of 

 the ridges to the base at the lowest point of each serration, gives the whole spine a jointed 

 appearance; but a. close inspection of the floor of the spine itself between the ridges 

 shows no sign whatever of any break in its perfectly smooth surface. The diameter of 

 the spines is only about one-tenth of a millimeter, and yet it gives room for an exquisitely 

 regular division of its periphery by seventy or more delicate ridges, every fourth one 

 higher than the intervening, ami all broken at minute interval-: by uniform serrations 

 i pi. 26, fig. 2 l. The preservation of these structures from carboniferous times is only less 



