898 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. [20] 



is narrow, and the two extremities, whicli are swelled and sack-like 

 especially the upper one. The latter and the middle part are bent over 

 and cover the lower part sometimes entirely. In the long form of the 

 worm the receptacle was found always more or less straight (Fig. 12g). 



The spermatophores are numerous and of various forms. The ovaries 

 are long and comparatively very narrow, developing the ripe ova at 

 their middle (Fig. 12r). 



The segmental organs are long and narrow (Figs. 12n and 12o); not 

 surrounded by globular cells. 



The integument is very tough. The spines are slightly curved j the 

 angle between the two prongs is in the anterior spines nearly a right 

 angle, but in the posterior spines of much smaller aperture. (Fig. 12, 

 e. d.) 



Of this species exist two different sized forms. One is about 18<'°» 

 long and 2"^™ broad. The other is only 5"™ ]ong by l^"^"^ to 1™™ 

 broad, Both forms are found fully matured, and both differ some- 

 what anatomically from each other. Intermediate forms are found, but 

 not very numerous. In one of two neighboring ponds both forms are 

 found, and intermediate ones between them. In the other pond or lake 

 I have as yet found only the smaller form, and no intermediate ones 

 (Fig. 12a and 6). 



Mahitat. — California, San Francisco. , In Laguna del Mercedes only 

 the smaller form. In Mountain Lake or •' Marine Hospital Pond" both 

 forms are found. In " Laguna del Tache" only the smaller forms. 



The following species are sufidciently well described to be recognized, 

 but not sufficiently enough to enable me to arrange them systematically 

 in the genus. For their characteristics I must refer to their respective 

 describers. 



LiMNODRiLus TJdekbmianus Gla^. 



Syn. : L. TJdehetnianus Claparede, Recherches anatomiques 8ur les Oligoohaetes, prz. 

 Q7,- Geneva, 1862. 



LiMNODEILUS HOFFMEISTERI Clap. 



Syn. : L. Hoffmeisteri Claparede, I. c, prz. 32. 



LIMNODRILUS GLAPARiGDiANUS Batzel. 

 Syn. : L. Claparedianus Ratzel, Z. f. ^Yissen8cllaftl. Zoologie, Bd. sviii, s. 563 to 591. 



All of the above three species are found in Europe, 

 Gen. GAMPTODEILUS nov. gen. 



Nervous system. — The cephalic ganglion is both anteriorly and posteri- 

 orly emarginated, and in this respect resembling all other genera except 

 Spirosperona. 



Generative system. — The copulative organs are much elongated, and 

 partly surrounded by spiral muscles, one end of which is attached to 



