BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND. 95. N:O 16. 1k 
In other respects this genus resembles Tubifex and 
Psammoryctes. The shape of the efferent ducts is the most 
prominent characteristic of the genus. 
The three species as yet known are easily characterized. 
a. comb-like spines present; the receptacle is bent, not glo- 
bular. The oviduct is double. I. Perrierui n. 
b. comb-like spines present; the receptacle is bent, not glo- 
bular. The oviduct single. I. sodalis n. 
ce. no comb-like spines; the receptacle is globular, not bent; 
the oviduct is single. MET fragulisen. 
FA Perrieri n; sp- 
The efferent duct is shorter than the atrium and the 
penis together, but of nearly the same length as the atrium 
alone. The penis seems to have no chitinous sheath, is very 
short and conical, its lower end not being thicker than its 
midle. 
The oviduct is double, the interior one ig chitinous, ex- 
tended, funnel-shaped and somewhat bent and gradually ta- 
ering towards the exterior porus. The exterior oviduct is 
sacklike, and also considerably tapering towards the exter- 
nal end. 
The receptacle is bent at the top, and not globular. 
Comb-like spines present as well as forked ones and hair- 
spines. Length of the body about 15 m.m. The worm 1s 
thickest at the middle. 
Habitat: California, Fresno Co, in ponds round Dry Creek 
and Kingsriver, and in irrigation ditches on the prairie. 
I. sodalis n. sp. 
The efferent duct is slightly longer than the atrium and 
penis together. The lower end of the penis proper is glo- 
bular, and immediately above contracted. The oviduct is 
bell-shaped, widest at the lower or exterior end. No penis- 
sheath. The receptacle is very much bent in the shape of 
an 5, the top being considerably enlarged. Comb-like spines 
present, somewhat similar to the preceding species. The 
testes are situated in 10 segments or in the 12th to 22d 
setigerous segments. No differentiated hearts, only pulsating 
