On some Perichsetida' from Japan. Y61 



calciferous glands. The intestine begins in the XVIth segment; but 

 in this segment it is of less calibre than in the next in which it 

 attains its füll size. The usual pair of caeca are present. 



There are 4 pairs of „hearts" in segments X— XIII. 



The sperm-sacs are in segments XI and XII. The atria are very 

 inconspicuous but, as I have only a singie specimen, it is possible 

 that this is an individual peculiarity — the atria being simply undeve- 

 loped. On the other hand as against this view I may point to the 

 uther species of Japanese Perichcetidce described here. The atriuni in 

 this species consists merely as in P. masatakm of the muscular tube 

 which is curved ; there is no trace of the glandulär part of the atriuni 

 to be discovered. 



The ovaries are large and lie in the Xlllth segment. I could 

 find no egg-sacs. There are 4 pairs of spermatothecai in segments VI, 

 VII, VIII, IX. Each has a diverticulum, which has a very unusual 

 form, illustrated in Fig. 8. The diverticulum is longer than the pouch 

 and gives off a number of small globular sacs which show great 

 Variation in number and position. These little globular sacs aloue 

 contained sperm, and were, owing to their Contents, of a chalk white 

 colour. As they are subject to so much Variation, I have not thought 

 it worth while to give a special description of them; two varieties 

 are figured (Fig. 8). 



Periehceta masataJcw n. sp. 



Of this new form I have two specimens. The only complete in- 

 dividual is 5 inches long by 6 mm in breadth both anteriorly and 

 posteriorly; the worm has 90 segments. 



The external characters need no particular description; the only 

 point that may be specially mentioned is the existence of copulatory 

 papillae on the same segments as those which bear the orifices of the 

 spermatothecae, viz. Nos. VIII and IX. 



With regard to internal structure, there are three septa in front 

 of the gizzard; the five septa following the gizzard — especially the 

 first two of them — are strengthened and united to each other by 

 tendinous threads. The septa between the gizzard segments are as usual 

 wanting; the Oesophagus is pinkish in colour in segments XI and 

 XII ; this region no doubt represents the calciferous pouches of other 

 earth Worms; the intestine begins in the XVth segment, and there 

 are the usual pair of cseca in segment XXVI. 



Zool. Jahrb. VI. Abth. f. Syst. 50 



