3 CALIFORNIA ACADEMY OF SCIENCES. 
2. Rhynchelmis Hoffin. 
One pair receptacles in the eighth segment. A solitary albuminous gland 
in the ninth segment. The postseptal secondary vessels are simple, the preseptal 
ones are feathered and branched. Spines are entire. Cephalic lobe filiform.* 
3. Sutroa n. gen. 
Seminal receptacles consist of several pairs of lobes, entire or forked, which 
all open in the so-called albuminous gland in the eighth segment. A solitary 
albuminous gland in the eighth segment. Preseptal and interseptal secondary dor- 
sal vessel are branching and feathered. Postseptal vessels are gastric, not feathered 
nor branching. Spines simple, not forked. Cephalic lobe filiform. 
It will thus be seen that Sutroa is nearly allied to the two other genera of 
the sub-family, the most prominent characteristic being the concentration of the 
receptacles and their opening into the albuminous gland. But the vascular system 
also shows some great peculiarities, which will soon be fully described. 
As only one species is known of the genus Swtroa, the generic and specific 
characteristics will here necessarily be considered together. 
Sutroa rostrata n. gen. et sp 
Habitat—l\ have found this species only in Mountain Lake, near the Marine 
Hospital. west of San Francisco, California. It occurs here only on the north 
shore, Just at the mouth of a small spring, which empties into the lake. It 
lives in the richest mud, between the roots of aquatic plants, probably with the tail 
vibrating in the water. When captured and set free in the water, the worms swim 
rapidly through a peculiar wavy motion of the body, showing to advantage its 
really magnificent iridescent colors, found to the same degree in no other fresh 
water annelide. The color of the body is very similar to that of Rhynchelmis limo- 
sella, a lively fleshy ved. 
The worm appears to be quite rare, as 1 did not succeed in getting over a 
dozen worms during each excursion. It also seems quite restricted to a certain 
part of the lake, where it lives in the rich mud at the margin of the bank. On 
the south, east or west ends of the lake I have looked for it in vain. 
The egg capsule or cocoons of Sutroa are in size nearly similar to those of 
Rhynchelmis, but in shape different. They can nearest be compared to the hanging 
nests of some birds—small, bag-shaped bodies, with a flat, somewhat concave top— 
suspended by a long semicircular membrane. Figure 15 gives an enlarged repre- 
*Vejdovsky, 1. c, pag. 52. 
