36 DR J. STEPHENSON ON 
usually six, varying from five to eight ventrally, and four, five, or six dorsally ; in the 
post-clitellial segments the numbers are about the same, except that nine were once met 
with in one of the ventral, and seven in one of the dorsal bundles. Ventral setze are 
absent in segment xii., in which also the dorsal setee are few or absent. 
The length of the sete: is on the average about ‘1 mm. ((095—'108 mm.). There 
is no appreciable difference in length between ventral and lateral sete, or between 
those in the anterior and those in the posterior part of the body. There is, however, 
a difference between the various setee of a bundle; the setze are disposed fan-wise in 
each bundle, and the outer sete are rather longer than the inner, the length de- 
creasing from the outer to the inner side with some regularity. In illustration, 
y 
Fic. 2.—A setal bundle of Marionina semifusea. 
the following figures may be given (cf. also fig. 4); the numbers represent the 
lengths of successive setze from outer to inner side of the bundles :— 
099 099 09 0855 0855 0855 
Venhioliceee 099 099 0967 09 ‘09 ‘09 
‘101 ‘101 101 ‘101 099 099 
"101 "101 099 099 0945 
099 0945 0855 09 
ieee 0945 0922 ‘09 0922 
‘0967 0967 0922 09 
01 ‘0967 ‘09 ‘0877 0832 
As regards the alimentary canal and its appendages, the pharynx has the usual 
form, and occupies segments ii.—1i1. ; the cesophagus is narrow, and begins to be clothed 
by chloragogen cells in segment iv.; the tube, though still narrow, dilates a little 
in segments 1x.—x.; 1t is again very narrow in the genital segments, and finally swells 
and assumes the usual characters of the intestine in segment xiv. ‘There are no pepto- 
nephridia. As remarked by SouruERN, the septal glands are large (Pl. I. fig. 2); they 
extend farther back than usual, one pair being situated always in segment vii. 
(cf. SourHERN), and there may be a pair in segment vii. ‘he chloragogen cells are 
of a very decided brown. 
The dorsal vessel begins in segment xiv. (xii. SOUTHERN), and bifurcates at the 
junction of prostomium and first segment ; the two branches into which it divides reunite 
ventrally in segment iv. to form the ventral vessel. The lateral commissural vessels 
are four on each side; the first begins above in segment ii. and ends below in the 
