N.\I:l:.\TIVK (if THE CR1 



285 





a pair of limbs tutted inwards oyer the mouth a* development pBoeeeda, in fact 'foot- 

 jaws' as in other Arthropoda. In many points of internal anatomy Peripatus pro 

 itself to be a most archaic form, and the early stages in the development of the egg have 

 been .shown by Balfour 1 and Sedgwick 1 to he of a most remark,-! ble character. It is prob- 

 able that we hare existing in Peripatus* form nearly allied to the ancestral progenitors 

 ofaD insects, and that the condition of the tracheae in Peripatm repre early 



in the history of the development of these organs which was pawned through by the 

 ana T all forma respiring by means of traeheca The trachess Hwne probably 



developed in the first tracheate ; 1 1 j i 1 1 1 ;i 1 -: out of skin glands scattered hII over the body. 

 In the higher forms they have become restricted to certain definite positions by the 

 action of natural selection. 



'■'■ That Peripatus is a very ancient form is proved by its wide and peculiar geographical 

 distribution. Speeiee of the genus occur at the Cape of Good Hope, in Australia, New 

 Zealand, in Chili, in British Guiana, in the Isthmus of Panama and its neighbourhood, 

 and in the Wed Indies. • 



'■'' The animal is provided with a pair of large glands, secreting a viscid fluid, which 



Kl<;. 1 14. —A right leg of PtriptUu* capen*i» ; 

 viewed from the anterior surfcv< 

 Balfour). 



Vv,. 115.— A left leg of Pvn 



capetuis; viewed from the 

 iriser surface (after Balfour). 



it has the power of projecting from two papillae placed one on either side of the mouth. 

 When it is irritated it discharges this fluid with great force and rapidity in fine 

 thread-like jets, which form a sort of network in front of the animal, resembling a 

 spider's web with the dew upon it, and appea if by magic, so instantaneously is 



it emitted. 



"The viscid substance, which is not irritant when placed on the tongue, is excessively 

 tenacious like bird lime, and the jets of it are apparently used, not only for defence, but 

 also to procure small insects for prey. 



' Qmui. r. Bei., X.S., vol. xix. pp. 431-433, I '., vol. xxiii. pp. B13-3W, 1883. 



