Two New Species of Pti/chodera. 209 



gonads in the anterior region. No ova or spermatozoa, however, were 

 found in the tail region as in the genital pleurae. These globules 

 have been found in the gonads of other species, and have been 

 supposed to be nutrient matter for the developing ova. Their 

 occurrence in the tail region, which is so often divided off in this 

 species to form new individuals, naturally suggests that their 

 function here is the sustenance of this proliferated part while 

 regeneration of collar and proboscis is going on. 



PTYCHODERA NATALENSIS, n. sp. 



Proboscis. This organ is relatively short, and was not observed 

 to vary much in the living animal. It was about 11 mm. in length 

 from the anterior margin of the collar, dome shaped, and well sunk 

 in the collar in the living animal. When treated with chloral hydrate 

 and subsequently a weak solution of chromic acid, the collar region 

 became contracted, exposing the proboscis to its neck : from this 

 point to the distal end it measured in the preserved condition 9'5 mm. 

 The breadth of the proboscis was in the living condition 9 mm., pre- 

 served 8 mm. The colour of the proboscis was markedly whitish as 

 compared with the remainder of the body, there being only a some- 

 what faint tinge of yellow. 



CoUttr. In the living condition this organ measured 6 mm. in 

 length and 8'5 mm. in breadth. It was, like the proboscis, quite 

 smooth, showing no longitudinal striping, but with a distinct annu- 

 lar groove round its postei'ior border. In colour it was of a distinct 

 though rather dull yellow. When preserved this part of the body 

 underwent greater change than any other, its dimensions being 

 altered to 4 mm. in length (on the dorsal side), 6 mm. in breadth 

 anteriorly, and 9 mm. in breadth posteriorly, the anterior end thus 

 having contracted considerably ; longitudinal furrows appeared, and 

 the posterior furrow was still evident. This shrinking of the collar 

 exposed the base of the proboscis, whose point of attachment seemed 

 very slight and easily damaged (cf. condition of some large species 

 without proboscis noted by Spengel). The longitudinal contraction 

 of the collar was greater on the ventral side, where it measured 3 mm., 

 so that the proboscis, collar, and anterior part of the body were bent 

 somewhat ventrally. 



Brancliio-ycnital region. This is of great length. It was broken 

 up, in digging for the specimen, into four pieces. The largest piece 

 (with proboscis and collar attached) was, in the preserved condition, 

 90 mm., the others 56, 42, and 16 respectively, so that the total 

 length of this region was a little over 2(JO mm. The most striking 



14 



