24 PERIPATUS CHAP. 



tion : South Africa (Cape Colony, Natal, and the Gaboon), New Zealand, 

 Australia and Tasmania, New Britain, South and Central America and the 

 West Indies, the Malay Peninsula [and Sumatra ?]. 



The genus Peripatus, so far as adult conformation is concerned, is a very 

 homogeneous one. It is true, as was pointed out by Sedgwick, that the species 

 from the same part of the world resemble one another more closely than 

 they do species from other regions, but recent researches have shown that 

 the line between them cannot be so sharply drawn as was at first supposed, 

 and it is certainly not desirable in the present state of our knowledge to 

 divide them into generic or subgeneric groups, as has been done by some zoolo- 

 gists.^ The colour appears to be highly variable in species from all regions ; 

 it is perhaps more constant in the species from the Neotropical region than 

 in those from elsewhere. The number of legs tends to be variable whenever 

 it exceeds 1 9 pregenital pairs ; when the number is less than that, it is usually, 

 though not always, constant. More constant points of difference are the form 

 of the jaws, the position of the generative orifice, the presence of a recejDta- 

 culum seminis and a receptaculum ovorum, the arrangement of the primary 

 papillae on the distal end of the feet, and above all the early development. 



South African Species. With three spinous pads on the legs and feet, 

 with two primary papillae on the anterior side and one on the posterior 

 side ; outer jaw with one minor tooth at the base of the main tooth, inner 

 jaw with no interval between the large tooth and the series of small ones ; 

 last fully developed leg of the male with enlarged crural gland opening on a 

 large papilla placed on its ventral surface ; coxal organs ^ absent ; the nephri- 

 dial openings of the 4th and 5th pairs of legs are j)laced in the proximal 

 spinous pad. Genital opening subterminal, behind the last pair of fully devel- 

 oped legs ; oviduct without receptacula seminis or receptacula ovorum ; the ter- 

 minal unpaired portion of the vas deferens short. Ova of considerable size, but 

 with only a small quantity of yolk. The embryos in the uterus are all nearly of 

 the same age, excej^t for a month or two before birth when two broods overlap. 



The following species are aberrant in respect of these characters : Peri- 

 patus (Opisthopatus) cinctipes, Purcell (Cape Colony and Natal), presents a few 

 Australasian features ; there is a small receptaculum seminis on each oviduct, 

 some of the legs are provided with well-developed coxal organs, the feet 

 have one anterior, one posterior, and one dorsal papilla, and the successive 

 difference in the ages of the embryos in the uterus, though nothing like that 

 found in the Neotropical species, is slightly greater than that found in other 

 investigated African species. Several pairs of legs in the middle region of 

 the body are provided with enlarged crural glands which open on a large 

 13apilla. Male with four accessory glands, opening on each side of and behind 

 the genital aperture. P. tholloni Bouvier, Equatorial West Africa (Gaboon) 

 shows some Neotropical features ; there are 24 to 25 pairs of legs, the 



^ The following genera or subgenera have been proposed : Peripatus for the 

 Neotropical species, Peripatoides for the Australasian, Peripatopsis and Opisthopatus 

 for the African, Paraperipatus for the New Britain species, and Eoperipatus for the 

 Malay species. 



2 Coxal organs are furrows on the ventral surface of some of the legs, with tumid 

 lips and lined by smooth non-tuberculate epithelium. It appears that they can be 

 everted. 



