754 The American Naturalist. [August, 
chæta have rightly treated this species cautiously, there being no data 
to indicate its position in the system. That Beddard, in his recent 
Monograph has seemed uncertain even of the Enchytreid nature of 
the form, has led me to make a brief statement of its anatomical char- 
acters. 
Setze, as stated by Leidy, are restricted to the ventral series of bun- 
dies. That these are truly the ventral bundles is shown by the posi- 
tion of the nepridial openings at the same level, and the relation of the 
bundles to the lateral line. ‘There appears to be no glandular replace- 
ments of the dorsal sete. The complete, typical seta bundle consists 
of two pairs, an outer of larger and an inner of smaller setz, disposed 
symmetrically. Such bundles were rarely present in the material ex- 
amined, and were confined to the ante-clitellar region. In some speci- 
mens they were entirely absent. Behind the clitellum, four, or even 
three, setæ were seldom found, two being the rule, and on a variable 
number of the posterior segments only one. Often some of the seg- 
ments were without sete. This irregularity in distribution, the fre- 
quent absence of setæ on a somite, and the fact that the posterior pairs 
were usually the outer or larger sets, indicate a retardation in the suc- 
cessive production of new pairs of setz, and a consequent tendency 
toward a reduction of the number in the bundle. 
In form, the setz are peculiar, being very stout, swollen in the mid- 
dle, blunt-pointed and slightly curved externally and hooked internally. 
A cephalic pore is present between the prostomium and peristomial 
ring; but no dorsal pores were observed, though this is not conclusive 
evidence of their absence. 7 
The inter-segmental septa, from the second to the sixth inclusive, are 
very thick and’ muscular, and the last three of these, namely, iv-v, v- 
vi, and vi-vil, bear prominent septal glands on their anterior faces. 
The bundles of ductules from these glands open as usual on the surface 
of a prominent dorsal pharyngeal pad, which was the usual structure. 
The testis papillz are united into a transverse ridge of simple col- 
umnar cells. The alimentary canal presents no marked enlargements, 
constrictions or saccular outgrowths. Its musculature is unusually 
powerful, and the two sets of fibres cross in a trellis-like arrangement, 
which is complicated at the septa. 
The pepto-nephridia (salivary glands) are a pair of branched tubu- 
lar structures in somite v, and are similar to those of several species of 
Fridericia with which they have been compared. 
_ The ante-septal portion of the nephridia is small, and consists mainly 
of the funnel; the post-septal is large, with a prominent dorsal lobe, 
