CALIFORNIA ACADEMY OF SCIENCES. 



The exterior ixjiuhi of tlie atriiiin is in Siitroa surrounded by strong muscu- 

 lar swellings, and the atrium itself forms a kind of penis, which probably is to some 

 degree jtrojective. 'I'lic exterior surface of the atrium is nowhere covered with 

 glands, as is the case in Rhjnchelnm, but consists of a long, narrow duct of a 

 uniform width (Fig. G, atr., and Fig. 14, atr.). No basal glands. 



The seminal vesicle consists of an enormous sac -like body, entirely filling 

 the twenty segments occupied by the atrium and the efferent ducts. 1 did not suc- 

 ceeil in linding the place at which it was attached to the atrium. 



The most characteristic interior organ, however, is the solitary body, for 

 which 1 here adopt the name given by Vejdovsky, glandula albuminifera or albumi- 

 nous gland. I am, however, by no means fully satished of the functions of this 

 organ, and its structure seems somewhat dillerent from that of the albuminous 

 glands of Rhijnchelmis and Lumbriculus. The solitary albuminous gland of Siitroa 

 opens in the center of the ventral part of the eighth segment (Fig. 14, gl. alb., and 

 Fig. 10). It has the shape of a glolnilinis body, connecting by a narrow neck 

 with the body wall and opening through an external large porus. Hut tlie 

 histological construction of this gland is quite different from the gland described 

 by Vejdovsky in Lwnbrlcului^* and in R/u/ncItelmis.f 



In till' latter two genera this organ is distinctly glandular, but in Sutroa it is 

 of nearly the same construction as the receptacles, being covered by smooth epithe- 

 lium, under which are found numerous long and narrow cells (Fig. 1"). 1 have, 

 however, no reason to doubt but that these organs are analogous in all the three 

 genera. 



The receptacles in Sutroa consist of tjiree pairs. In Rhijnchelmis and Luinbricn- 

 luti we liiid the rece[itacles o[)en each in a separate porus; in Sutroa. however, there 

 exists the great anomaly that all the six seminal receptacles open into the narrow 

 neck of the above described solitary gland (Fig. 10, re. sem.). These receptacles 

 consist of long uari-ow sacks, containing full}' developed spermatozoa (Fig. 8). 

 Generally there are three pairs of receptacles, but in some specimens 1 found three 

 receptacles on one side and only two on the other. Sometimes the interior end of 

 a receptacle is forked; generally, however, they are entire. That these elongated 

 bodies are real receptacles is proved by their being full uf spermatozoa fully devel- 



• Vejdovsky, Hystoin der Oligoohwteu. Tiif. XII, Ml ^. iilb. 

 t Slime. All stud. KbyDchelinis. Inf. Will, I''i>{. 17. 



