NEW SPECIES OF PEBICH^TA. 203 



the segments T./^iv VI. /vii., vii./viii., with 13 chset^e on seg- 

 ment VII., between the lines joining the pores. 



The first dorsal pore is between segments xii./xiii. ; the pores 

 are invisible on the clitellum. 



The chcetal ring is not complete : there is a distinct dorsal gap, 

 as may be premised from the existence of the dorsal longitudinal 

 band of colour. There is also a ventral gap, about twice the 

 width of a normal gap. 



The chaetse of segments v., vi., vii. are distinctly larger than 

 those on other segments (figs. 2 e, 2f), while those of segments 

 IT. and VIII. are intermediate in size ; in these segments, too? 

 the cbsetse are larger on the ventral and lateral surfaces than 

 dorsally. The length of the normal chseta is 0'228 mm., while the 

 larger ones measure 0'341 mm. Similar enlarged chaetse have 

 ibeen described in P. liawayana, Rosa, on the 3rd, 4th, and 5th 

 segments, and in P. sandvicensis, Bedd., and others. 

 The chaetae number 22 on segment ii. 

 29 „ VI. 



„ „ 44 „ IX. 



50 „ XII. 



(The cuticle on segment xiii. was incomplete.) Further back 

 ihere were 54 on a segment. 



Internal Anatomy. — There are no conspicuously stout septa. 



The gizzard is tubular, not bell-shaped, and lies in segments 



Vlll., IX. 



The intestine was so rotten that a touch was sufficient to 

 tear it, and I am not certain whether there are or are not any 

 lateral caeca on the usual segment. I believe, however, that they 

 are absent. But a very exceptional, indeed, I believe, a unique 

 feature in the anatomy of Pericho'ta was observed : viz., the 

 •existence of a median, unpaired, ventral ccecum in segment xxil. 

 As the worm was opened from the side, in accordance with mv 

 usual procedure in dealing with worms of which I have only one 

 or two specimens, tliis ventral caecum was at once seen without 

 touching the intestine, but in attempting to search for the 

 normal paired caecum, the intestinal wall ruptured and broke 

 into pieces. 



The vascular system in the anterior part of the body showed 

 up well, on account of the light-brown colour of the blood ; the 

 ventral vessel was seen to be double in front of septum ix./x. — 

 ^s in several other specie?. 



Large " latero-intestinal " hearts occur in segments x. and xi., 



