Q2 
ZOOLOGY OF THE FAR EAST. 
the extrusion of the penis (cf. fig. 2). The penis ari.ses from the bottom of an invagi- 
nation of the surface, which may be called the penis-sheath. 
The ovary is particularly bulky ; attached anteriorly to septum lo/ii near the 
ventral body- wall, it extends backwards behind the prostate, and pushes septum 
11/12 back to the level of 12/13; it appears to be suspended b)^ strands which pass 
dorsoventrally. 
The ovisac is extensive, reaching as far as segment xviii. The funnel is a shght 
modification of peritoneal epithelium on both septum 11/12 and the adjacent body- 
wall ; the cells are small, cubical or low columnar, compacter than the usual peritoneal 
lining, thrown into folds, non-ciliated and with deeply staining nucleus. The duct 
passes straight down through the body-wall, and thus opens in groove 11/12. 
The ampulla of the spermatheca is of an inverted pear-shape, broad in compari- 
son with Its height; the narrower portion, the stalk of the pear, is above. The whole 
is placed vertically in the segment and reaches to not far from the dorsal parietes. 
There are no spermatophores, the contents consisting of a mass of matted spermatozoa. 
The duct, nearly equal in length to the ampulla, is broad and patent, and almost 
straight or somewhat bent forwards. The epithelium of the ampulla is cubical to 
columnar ; that of the duct is irregular in height, and the lining thus appears to be 
thrown into folds. 
Remarks. The genus to which the above species is most closely related is 
Branchiura ,^ at present represented only by one species, B. sowerhyi. 
In the main features of its anatomy K. japonica agrees with B. sowerhyi, as well 
as in possessing such a special character as the coelomic sac enclosing the terminal 
portion of the male deferent apparatus. This structure, known hitherto only in B. 
sowerhyi, seems to be of considerable morphological value; other peculiarities common 
to both, — the enormous size of the giant fibres of the ventral nerve cord, and the ventral 
position of the dorsal vessel, — may not have the same significance. 
It differs from B. sowerhyi in the absence of gills and in the presence of a well- 
marked penis, as well as in the possession of only a single pair of hearts, in segment 
ix, instead of two pairs, in ix and x. The last point is perhaps of no great value, 
but the other two appear to be of more importance. 
It is true that Michaelsen has more than once expressed the opinion that the 
presence of gills is not of much morphological weight. So in 1900 (8) he united B. 
sowerhyi and Ilyodrihis coccineus in the same genus, in spite of the absence of gills in 
the latter. In 1908 he writes (13): "Die Kiemen der Branchiura sind ja nichts 
' The limits of the genus BKancAn<)-a have undergone several changes. Established in 1895 by Beddard (2) for B. 
sowerhyi, largely on account of the presence of gills, it was united by Michaelsen in 1900 (8) with the worm known 
as Tubifex or Ilyodrilus coccineus, and in 1905 (12) with Taupodrilus (Benham, 1903, 4) ; in bringing these various worms 
together, Michaelsen was guided by the comparatively small importance he attributed to the presence of the gills in 
Beddard's species. His view was accepted by Benham, who in 1907 (5) described another species, similar to his pre- 
vious species of Taupodrilus, as Branchiura pleurotheca. In 1908 Michaelsen (13) himself obtained B. sowerhyi, and sub- 
jected it to examination, with the result that he found Beddard's description to be erroneous in certain respects, 
especially in making no mention of the paratrium,— a blind tubular diverticulum of the atrium ; it thus became necessary 
again to separate Branchiura from the other species, which (including /. coccineus) resume the name Taupodrilus. In 
1909 Michaelsen (14) gives the presence of gills, the presence of paratrium, and absence of penial setae as generic char- 
acteristics, as against Taupodrilus, which has penial setae, but no gills or paratrium. 
