On the Structure of Peripatus capensis. 229 



divarication of the ventral nerve-cords. The fact was considered 

 remarkable and dwelt upon in all accounts of Peripatus before the 

 existence of tracheae in the animal was known, and when it was 

 thought to be hermaphrodite ; but it is doubly remarkable now. 

 The fact shuts off at once all idea of Peripatus being a degenerate 

 Myriopod, the evidence against which possibility is overwhelming. 

 The bilateral symmetry and duplicity of the organs of the body, 

 the absence of striation in the muscles, of periodical moults of 

 the larval skin in development, and of any trace of a primitive 

 three-legged condition, taken in conjunction with the divarication 

 of the nerve-cords, are conclusive. The parts of the mouth are 

 not to be regarded as degraded to any great degree ; and homo- 

 logies for some of them, at least, may perhaps be found amongst 

 the higher Annelids. The structure of the skin is not at all unlike 

 that in some worms, especially in its chitinous epidermic layer, 

 which occasionally strips off in large pieces as a thin transparent 

 pellicle. The many points of resemblance of Peripatus to Annelids 

 need not be dwelt upon ; they led to its former placing in classi- 

 fication ; but it is difficult to understand bow the very unannelid- 

 like structure of the foot-claws did not lead others beside De 

 Quatrefages to draw a line between Peripatus and the Annelids. 

 In being unisexual, Peripatus is like the higher Annelids, as well 

 as the whole of the higher Tracheata. To Insects Peripatus shows 

 affinities in the form of the spermatozoa, and the elaboration, 

 structure, and bilateral symmetry of the generative organs, though 

 there is a very slight tendency towards the unilaterality of Myrio- 

 pods in the male organs. 



To Insects, again, it is allied by the five-jointing of the feet and 

 oral papilla? and the form and number of its claws. It should be 

 remembered that spiders' feet are two-clawed, as are those of some 

 Tardigrades, and that some of these latter forms have two-clawed 

 feet in the early condition even when they possess more claws in 

 the adult state. In Newport's well-known figure of the young 

 lulus with three pairs of limbs, the tips of these latter are drawn 

 with two hair-like claws ; these are not mentioned in the text. 

 To the ordinary lepidopterous larva the resemblances of Perijxctus 

 are striking — as, for example, the gait, the glands (so like in their 

 function and position to silk-glands), the form of the intestine, and 

 the less perfect concentration of the nervous organs, as in larval 

 insects. To Myriopods Peripatus is allied by the great variety 

 in number of segments in the various species, in its habits, and in 

 these especially to lulus. The parts of the mouth perhaps show a 

 form out of which those of Scolopendra were derived by modifica- 

 tion ; but the resemblance may be superficial. Our knowledge is 

 not yet sufficient to determine such points. The usual difficulties 

 occur in the matter. Segments may have dropped out or fused ; 

 and their original condition may not be represented at all in the 

 process of development. In structure Peripatus is more like Sco- 

 lopendra than lulus, viz. in the many joints to the antenna; (in 

 Chilognaths never more than fourteen), in the form of the sperma- 



