THE ANATOMY AND DEVELOPMENT OF PERIPATUS 

 NOVAE-BRITANNIAE. 



By ARTHUR WILLEY, D.Sc. Lond., Hon. MA. Cantab. 



With Plates I— IV. 



The only previous notice of the occurrence of Peripatus in any of the islands 

 of the Indo-Pacific region is that of a species recorded from Sumatra in 1886 by 

 Dr R. Horst (8) 1 , and subsequently named P. sumatranus by Sedgwick (19). One specimen 

 only was found in the Museum at Leyden in a bottle containing insects said to have 

 come from East Sumatra. Its general characters (e.g. number of spinous pads on legs, 

 position of generative orifice, and shape of primary papillae) were those which are 

 common to all the Neotropical species of Peripatus. New Britain is geographically 

 an intermediate locality between Sumatra and the Neotropical region, but the Peripatus 

 which occurs there does not possess a single external structural feature of importance 

 (apart from sexual dimorphism) in common with the Neotropical species ; although by 

 a singular coincidence the female has the same number of claw-bearing legs — 24 pairs — 

 as the alleged Sumatran species. Under these circumstances, the evidence that the 

 latter was actually found in Sumatra, which Sedgwick regarded as inconclusive, must 

 appear more than ever worthy of suspicion. Nevertheless, the fact that this unique 

 genus is represented in New Britain by the species which forms the subject of the 

 present paper, makes it very desirable that the islands of the Malay and Melanesian 

 Archipelagos should be carefully watched for their peripatine possibilities. For Peripatus 

 is one of those animals whose presence lends a distinct character to the fauna of any 

 region. 



The fact was definitely established by Sedgwick, about ten years ago, that the 

 species of Peripatus hitherto described could be arranged in three groups in accordance 

 with their geographical ranges, namely, Neotropical, Australasian and Ethiopian ; those 

 from any one of these regions having certain common features. As I have already 

 pointed out in a preliminary diagnosis (25), the New Britain Peripatus cannot be 

 associated with one of the three groups named above, but forms the type of a fourth 

 group which, in correspondence with the nomenclature adopted by Sedgwick, may be 

 designated Melanesian. 



Account of Material. The material at my disposal consisted of thirteen specimens, 

 which I obtained myself from' the bush at an elevation of several hundred feet above 



1 The numbers in brackets refer to the Bibliography at the end of the Paper. 



W. 



1 



