

160 



A NATURALIST ON THE "CHALLENGER. 



jj 



The sexes are distinct in Peripatus. The males are much 

 smaller and fewer in numbers than the females. The females 

 are viviparous, and the process of development of the young 

 shows that the horny jaws of the animal are the slightly 



modified claws of a pair 

 of limbs turned inwards 

 over the mouth as de- 

 velopment proceeds ; in 

 fact, " foot-jaws," as in 

 other Arthropods. 



Before I studied 

 Peripatus at the Cape, 

 nothing was known of 

 its manner of develop- 



HEAD OF EMBRYO OF PERIPATUS CAPENSIS, SHOWING meilk, nOl 01 Llie iaCl 



THE DEVELOPMENT OF THE ,AW. ^ ft ^^^ ^ ty 



means of tracheae. It was generally placed with the Annelids, 

 though its alliance with the Myriapods had been suspected by 

 Quatrefages. 



That Peripatus is a very ancient form is proved by its wide 

 and peculiar distribution. Species of the genus occur at the 

 Cape of Good Hope, in Australia, in New Zealand, in Chili, in 

 the Isthmus of Panama and its neighbourhood, and in the West 

 Indies. If its horny jaws were only larger they would no doubt 

 be found fossil in strata as old as the Old Eed Sandstone at 

 least. 



The animal is provided with large glands, which secrete a 

 clear viscid fluid, which it has the power of ejecting from two 

 papillae, placed one on either side of the mouth. When the 

 animal is touched or irritated, it discharges this fluid, with great 

 force and rapidity, in fine thread-like jets. These jets form a 

 sort of net-work in front of the animal, which looks like a 

 spider's web with the dew upon it, and appears as 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 when I 

 put some on a slip of glass, some flies approaching it were at 

 once caught and held fast. It appears from the observations of 



