98 Canadian Record of Science. 



Diplopoda in their general appearance much more closely 

 than either of the preceding families. Sir Wm. Dawson, 

 who first discovered their forms in the Palaeozoic rocks } 

 classed them with the Diplopoda, and spoke of them as the 

 oldest "gaily worms" known. Sir William's figures would 

 indicate that the back (not the front part as Scudder says) 

 was the more elevated. While first found in the erect 

 stumps of Sigillarian trees at the Joggins, they have since 

 been detected in the Coal Measures of Great Britain and on 

 the continent of Europe. Possibly also some species found 

 in the Dyas of Bohemia may belong to this family. Two 

 species have been found at Mazon Creek. 



As regards the development of the Myriapods, Dr. Scud, 

 der says that in the early life of Pauropus and the Diplo- 

 poda we have what may be fairly considered a true larval 

 form, in which for a brief period after leaving the egg the 

 body, much shorter than in after life, is provided with three 

 pairs of legs, borne on the anterior segments of the body. 

 These segments are never fully provided with legs, though 

 most of the segments posterior to them, both those which 

 exist during the larva! state and those which originate sub- 

 sequently, bear each two pairs. In the Chilopoda on the 

 other hand, although the appendages of the anterior 

 segment develop earlier than those behind them there is no 

 true larval condition, or perhaps one may say a larval con- 

 dition is permanent, in that the same anterior legs become 

 early and permanently developed, as organs subsidiary to 

 manducation, while each segment of the hinder part of the 

 body develops only a single pair of legs. 



To close these remarks it may be said that nine genera 

 of Palaeozoic Myriapods have been recognized in the Coal 

 Measures, and two in the Devonian rocks of Scotland. 

 While of those found at St. John and which are supposed 

 to be older, the genera are the same as those of the Coal 

 Measures or are nearly related to them. 



The air-breathing articulates of the Plant bed of St. John 

 so far recognized, consist of : — 

 Insects, nine species of eight genera 9 



