ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



833 



of the primary form of the Myriopods, while the Chilopods are a 

 secondary, less primitive group. The two pairs of head appendages 

 found in the latter have no representative in the former, nor indeed 

 do their morphological similars exist in any other Tracheate ; it is 

 proposed to distinguish them as malipedes. A comparative table is 

 given which may be here reproduced. 



Hexapoda. 



]st Arthromere Antennae 

 (preoral). 



2nd ditto 



(postoral). 

 3rd ditto 

 4th ditto 



5tli ditto 

 6th ditto 



Mandibles . . 



1st Maxillae 

 2nd Maxillae 



1st pair of 

 Baenopoda. 



Arachnida. 



Wanting 



Chelicerae . . 



Pedipalpi . . 

 1st pair of 



BsBnopoda. 

 2nd ditto 

 3rd ditto ,, 



Chilopoda. 



Antennae.. 



Protomalae 



DeutomalcB 

 1st Malipedes . . 



2nd ditto . . 



Chilognatha. 



Antennae. 



Protomalae. 



Deutomalae. 

 1st pair of 



Pedes. 

 2nd ditto. 



1st pair of Pedes 3rd ditto. 



The author finds that the larval diplopod Myriopod is a six-footed 

 Tracheate, though neither its mouth-parts nor primary legs are 

 directly homologous with those of the Hexapoda. It would seem 

 that the Chilopod arose from a diplopod or diplopod-like ancestor, 

 with a cylindrical body, narrow sternites, and three pairs of legs, 

 which represent those of the larval Chilognath. Thus the first six 

 appendages of the embryo Geophilus correspond to the antennae, two 

 pairs of mouth-parts, and three pairs of legs of the larval lulus. A 

 complete parallel seems to obtain between the diplopod Myriopods 

 and the phyllopod Crustacea. The Myriopod must have branched off 

 from the tracheate stem by an ancestor much more primitive than 

 Scolopendrella, a form which, in opposition to Eyder, Packard looks 

 upon as a hexapod, earlier than but allied to Gampodea. 



Pauropus does not justify its claims to a separate order, and is best 

 placed systematically in a second sub-order of the Chilognatha ; Eury- 

 pauropus may be looked upon as connecting Pauropus with Polyxenus. 



Development of Peripatus.* — In the existing dearth of facts re- 

 lating to the early stages of Peripatus, Dr. J. von Kennel's observa- 

 tions have an especial interest. He obtained his specimens, which 

 included upwards of one hundred of P. Edwardsii and a few of a new 

 species, from Trinidad. The new species is termed P. torquatus ; it 

 is by far the largest yet discovered, the female attaining a length of 

 15 cm. and a diameter of 8 mm., the male a length of 10 cm. ; it is 

 reddish-brown above, becoming paler below, the forehead and antennae 

 are black, a pale band separates the head from the body ; the number 

 of pairs of feet is also in excess of those of all other forms, viz. forty- 

 one to forty-two pairs. 



The uterus of Peripatus is always found to contain a large number 

 of embryos in all stages, from the segmented ovum to the mature 

 embryo ; hence the female is probably impregnated once only. The 

 ovum contains no nutritive yolk, thus the development from the 



* Zool. Anzeig., vi. (1883) pp. 531-7. 



