THE PE RIP ATI. 



157 



PAUROPUS HCXLEYI. 



A, enlarged 40 times B, antenna, enlarged 25C 



times. 



Another peculiarity of these animals is that they appear to possess no respiratory organs. There 



are no stigmata, and although the skin is very transparent, Sir John Lubbock could detect no tracheae 



in the interior of the body. The commonest British species 



(Pauropus huxleyi), which attains a length of one-twentieth of 



an inch, is an active little white creature, which may be found 



throughout the year among dead leaves and decaying vegetable 



matter in general. Two oval spots on the head are supposed to 



represent eyes. It appears to breed in the early autumn, and the 



newly-hatched young have only three pairs of legs. Sir John 



Lubbock describes a second but rarer British species (P. peduncu- 



latus), and others have been obtained in North America. 



ORDER IV ONYCHOPHORA. 



Many years ago the Rev. Lansdowne Guilding discovered in the 

 island of St. Vincent a curious worm-like creature frequenting dead 

 wood and the stumps of trees, which he regarded as probably a 

 worm, and described (in 1825) under the name of Peripatus juli- 

 formis. Its true position has been frequently discussed, and for 

 a long time it seemed to hover between the Annelids and the 

 Myriopods, until the investigations of Professor Moseley, during the 

 voyage of the Challenger, caused the scale finally to descend on the 

 Myriopod side. These creatures are convex and worm-like, with 

 their segmentation not particularly distinct, and the integuments 

 of all parts of the body soft. On each side of the body are a 

 number of short legs, terminated by a rudimentary jointed part, and a -pair of hooked claws. 

 The head bears a pair of simple, annulated antennae, and a pair of simple eyes ; the mouth, 

 which is below, has tumid lips, and within these two pairs of horny jaws. Respiration is 

 effected by means of tracheae, which, however, are not connected into a regular system, but each 

 respiratory aperture, of which a great number are scattered over the skin of the animal, 

 gives origin to a small branched tuft of breathing tubes. As Professor Moseley says, we 



have here probably the first stage in the 

 evolution of tracheae, which would in- 

 dicate that the " air-tubes were developed 

 in the first tracheate animal out of skin 

 glands scattered all over the body." Of 

 the internal structure of Peripatus we 

 need only say that it differs from that of normal Myriopoda in the wide separation of the 

 ventral nervous cords, and that it has greatly developed glands, called by Professor Moseley 

 " slime glands," probably homologous with the salivary glands of other Myriopods, which secrete in 

 abundance a clear viscid fluid. This is ejected by the animal from a pair of papillae placed at the 

 sides of the mouth, in fine, thread-like jets, which combine to form a sort of network in front of the 

 animal. It would appear that the emission of this slime is partly for defensive and partly for offensive 

 purposes, as it takes place when the creature is irritated or handled, and is also employed, according 

 to some observers, in the capture of insects for food. The Peripati are viviparous. They reside prin- 

 cipally in rotten wood, are nocturnal in their activity, and walk in the manner of caterpillars, with 

 the body much extended. According to Professor Moseley's observations on the Cape species 

 (Peripatus capensis), the food consists of vegetable matters ; but according to Professor Huttoii the 

 New Zealand one (P. novce-zealandia>) feeds partly upon insects. The Peripali must be regarded 

 as representing a very early stage in the evolution of the Arthropods from the Vermes, and hence 

 their form is probably of great antiquity. Their peculiar geographical distribution would also point 

 in the same direction, seeing that species of the jrenus are found in Central America and the West 

 Indies, in Chili, New Zealand and Australia, and at the Cape of Good Hope. 



\V. S. DALLAS. 



PERIPATUS CAPENSIS. (Nat. Size.) 



