OF CARBONIFEROUS MYRIAPODS. 287 



structure like that of modern Chilopoda, and no trace of the division between the dorsal 

 and ventral plates can be seen in any of them, the separation of the segments into two 

 sub-segments, as in Chilopoda, one of them greatly atrophied, could hardly be apparent 

 did it exist. But on the other hand, as we regard the second sub-segment of Chilopoda as 

 atrophied, we should expect to find it fully or partially developed in these creatures, which 

 of all known ancient types are certainly the most closely related to them. Yet we find 

 here no sign of anything more than the simplest possible, uniform, leg-bearing segments, 

 and of a very limited number. In one feature, however, they are not so simple as in 

 Chilopoda ; for, as stated, each is provided on each side with two pairs of mammillae, support- 

 ing very large bunches of spreading rods «"nd the rods themselves are sculptured in a very 

 remarkable way. This distinction between the two types, though more striking and notice- 

 able than any other, is in itself by no means so important as the others, but may be added 

 to the catalogue; and it must have some weight, from the total absence of appendages of 

 any sort (beyond scattered hairs) from the dorsal plates of Chilopoda. The position of 

 these rows of fascicles and of the legs indicates that the ventral plates were only a little 

 narrower than the dorsal, and probably of about the same extent as in the Archipolypoda ; 

 in this respect they would not differ to any important degree from modern Chilopoda. 

 The legs were different in form, but their poor preservation in the only specimen in which 

 they have been seen prevents anything more than the mere statement of the following 

 difference: while the legs of Chilopoda are invariably horny, slender, adapted to wide ex- 

 tension and rapid movement ; those of Palaeocampa are fleshy, or at best subcoriaceous, 

 very stout and conical, certainly incapable of rapid movement, and serving rather as props. 



These differences, which underlie every part of the body that is preserved in Palaeocampa, 

 show that while the general accordance of grand features compels us to look upon 

 Palaeocampa as a precursor of the Chilopoda, we must separate it from them in the same 

 way as we separate the Archipolypoda from the Diplopoda. For such a group the name 

 of Protosyngnatha is proposed, indicating its ancestral relations to the Chilopods, or Syng- 

 natlia, as they were called by Latreille. 



There are, however, two aberrant groups of living animals more or less closely related 

 to myriapods, and placed with them by some authors, with which also we should compare 

 Palaeocampa. The first of these is Peripatus, our knowledge of which has been so much 

 increased of late years, and especially by the researches of Moseley. 



In external appearance Peripatus resembles an annelid, but is furnished with a pair of 

 long, jointed antennae, and with numerous fleshy, tapering legs, each armed at tip by a 

 pair of claws; the legs, set wide apart, are obscurely jointed, the joints being perceptible 

 only at the extreme tip and on the apical half of the inner side, above which are the large 

 elongated openings into the nephridia. The entire body is of a leathery texture with no 

 external sign of segments, or of the separation of the head from the rest of the body, except 

 the appendages: namely, the legs, the nephridia opening on the legs, and the ordinary 

 appendages of the head. The same is true when the internal structure of the body is ex- 

 amined, for neither in the disposition of the muscles nor of the tracheal apparatus does it 

 appear that one could judge whether a pair of legs representad one or more segments of 

 the body ; even in the nervous system it is only indicated by a small ganglionic swelling 

 next each pair of legs. The tracheae are like extended cutaneous glands, in iependent of 



