10 EISEN, PRELIM. REPORT ON GEN. AND SPEC. OF TUBIFICIDA. 
II. Only one kind of spines, viz. forked spines. 
1. Penis and oviduct not surrounded by spiral muscles. 
Limnodrilus n. 
2. Penis and oviducet surrounded by a band of spiral 
muscles. Camptodrilus n. 
Spirosperma nov. gen. 
The cephalic ganglion anteriorly furnished with a large 
conical processus, which does not branch in the cephalic 
lobe of the body. The posterior margin is concave. The 
spermatophore is very long and narrow, and spirally coiled, 
surrounded by a pellucid sack-like membrane. The spines 
are of three kinds, hair-spines, forked spines and comb-like 
spines. The integument is thickly covered with dark con- 
vex papille. 
S. ferox n. sp. 
The penis sheath is chitinous, but only half as long as 
the penis proper, which is considerably swelled outside the 
penis sheath. The oviduct is single, muscular, not chitinous, 
and longer than the penis proper. The forked spines in 
the front segments are furnished with several prongs. The 
length of the body is about 20 m.m.; a cingulum is very 
conspicuous in adult specimens. 
Habitat: Sweden, Motala river, in shallow water, also in 
the lake of Ifö in Scania, where it was taken by Professor 
W. LILLJEBORG at a depth of 25 fathoms. 
Ilyodrilus n. gen. 
The cephalic ganglion both anteriorly and posteriorly 
emarginated. "The efferent ducts are broad; compared with 
those of other genera of the family, and also much shorter, 
never much exceeding the length of the atrium and penis 
together. The spines are of three kinds, viz. hair-spines, 
comb-like spines and forked spines, not all necessarily pre- 
sent in the same species. The prongs of the comb-like spines 
are much narrower in this genus than in Psammoryctes, and 
the striated membrane between the forks is of a much finer 
structure. 
