ClassiJicat{o7i of the Diplopoda. 285 



p. 161) are more or less in accord, Drs. Meiuert, Latzel, 

 Berlese, and Haase, merely retaining in their works the 

 family names Glomeridge, lulidte, Poljdesmid^, &c., have 

 put forward no classiflcatioa expressive of the idea that in 

 the Chilognatha the Glomeridse are a family highly special- 

 ized and sharply defined ; or, in other words, these authors 

 seem to have altogether underrated the systematic value of 

 the distinguishing characters of the genus. These characters 

 are as follows : — The copulatory appendages are at the poste- 

 rior end of the body ; the plem'a3 are distinct ; the anal plates 

 free ; the body is composed of not more than fourteen somites ; 

 the foramina repugnatoria form a single series in the dorsal 

 middle line ; the alimentary canal is not straight, and the 

 tracheae are branched. 



With this may be compared the structure of lulus as 

 typical of the rest of the Chilognatha. The co{oulatory ap- 

 pendages are in the seventh segment of the body 5 the pleurae 

 are not distinct ; the anal plates are surrounded by the last 

 body-ring ; the number of body-somites is great and variable ; 

 the foramina repugnatoria form a single series on each side ; 

 the alimentary canal is straight, and the trachese are tufted. 



In the case of all the genera allied to lulus it of course 

 cannot certainly be known whether the tracheae be tufted and 

 the alimentary canal straight or not ; but taking into consi- 

 deration the other points in common, it is perfectly fair to 

 presume, until evidence to the contrary is forthcoming, that 

 resemblance will be found to exist in these particulars also. 



With regard to the Polyzonidas, Brandt was apparently led 

 to the formation of his group Siphonizantia, Sugentia, or 

 Colobognatha from his inability, owing to the absence of 

 intermediate forms, to recognize the possibility of the conver- 

 sion of the masticatory jaws of an lulus into the sucking- 

 proboscis of a Polyzo7iium. 



A genus, Platydesmus, with mouth-parts in many respects 

 intermediate in character between the masticatory and sucto- 

 rial types, was, in 1843, described by Lucas, who pointed out 

 its resemblances to Polyzonium and Polydesmus. By New- 

 port, who abolished the group Sugentia and assigned to 

 Polyzonium and Si]}honophora a position near the lulidge in 

 his division Bizonia, this genus, which was probably known 

 to him solely from the description and figure publislied by 

 Lucas, was regarded as allied to Polydesmus. 



Gervais in this respect followed Newport, both authors 

 being apparently misled by the superficial resemblance be- 

 tween the two genera atforded by the presence of keeled seg- 

 ments in each. 



Ann. & Mag. N. Hist. Ser. 5. Vol. xx 20 



