ONYCHOPIIORA OF WEST AUSTRALIA. 



371 



orange papillee. Each ring liere hears burger and more separated 

 papilla^ whicli are quite white. They seem to correspond to the 

 wliite areas round papilla' of the dorsal surface. 



In both varieties an extremely fine light median line runs the 

 length of the dorsal surface. It may not appear so in all 

 specimens at a first glance. Tiiis, however, is due to the fact 

 that in the light brown specimens, where it seems clear, it runs 

 down the middle of a narrowband somewhat paler in colour than 

 the rest of the dorsal surface and rather free from papillfe. In 

 the dark specimens, on the other hand, this narrow band is 

 darker than the rest of the dorsal surface, and with the naked 

 eye or low power may be all that is observed. A iiigher magni- 

 fication will show that a very fine light line runs through it 

 medially, as in the light-coloured specimens. 



The longitudinal band of the dorsal surface referred to above 

 is related to a slight depression, the fine white line being an 

 extremely narrow groove. The narrow band was noted by 

 Bouvier, but the fine median white line escaped his notice. 



In both varieties there are always a number of clear white 

 papillae between the successive legs at about the ventral margin 

 of the flanks. These correspond, however, to the large papillae 

 of the dorsal surface and have merely lost the black pigment^ — 

 they are identical with the large clear pa})il]a? of the ventral 

 surface. 



The skin is thrown into a number of folds or ridges, as is usual 

 in Peripatus. There are about 14 of these between two similar 

 points opposite two successive legs. The ridges are to be seen 

 both dorsally and ventrally, but are not continuous round the 

 entire circumference of the body, for they are interrupted in the 

 middle of the dorsal surfa.ce by the longitudinal line. But for 

 this, however, some are continuous. Others ai-ise between these 

 lai'ger folds and do not run so far. Naturally those opposite the 

 legs are not continuous on to the ventral surface. The folds are 

 not all of tlie same width, but it can hardly he said that they aie 

 alternately wide and narrow in either variety. There is really 

 very little difference. 



Orat. Papilla.. 



The oral papillae are to be found in their usual position — there 

 is nothing of particular interest to add with regard to them. 



On many occasions slime was shot out from the openings of 

 slime glands on these oral papilla^ when the specimens were 

 touched. It was emitted in large quantities when the animals 

 were dropped on to v/ater containing a little formalin, and also 

 when the specimens were narcotised with chloioform. 



The Cepjialtc Region. 



Bouvier (3) lias described in considerable detail the rings or 

 ridges of the integument at the bases of the antenna? and in the 

 Proc. Zool, Soc— 1920, No. XX Y, 2:> 



