ENCHYTR^EID^E 29 



lower part, that is, from the ampulla to the pore, but the ampulla itself 

 is very thin-walled. In two specimens the ampullae rest in VIII, in 

 another specimen they are situated in VII. 



Atrial glands (pi. iv, fig. 3). There are five atrial glands open- 

 ing into the atrium. All possess long ducts, which in some of them 

 run far down into the penial part of the atrium, while others open 

 more directly. There are no circular muscles outside of the main 

 muscular bulb, but inside the bulb such muscles are seen to surround 

 e&oh group of ducts. 



Penial bulb (pi. iv, fig. i). The bulb contains two kinds of 

 glands distinguished by stronger or weaker staining reaction. In the 

 figure the more strongly stained glands are dotted. There are no 

 accessory glands. The inner glands are all narrow, only one or two 

 cells wide. 



MESENCHYTR^US FRANCISCANUS sp. nov. 

 pi. iv, figs. 4, 5#, 5c, 5<f, 5<?, and 5/5 and text-figs. 10 and n. 



Definition. Length 20 to 30 mm., width i mm. or over. Somites 

 about 78. Body strongly tapering toward both ends. Setae : laterals, 

 2, 2, 2, 2, 3, 3, 3, 3, 2, 3, o, 2, 2, 3, 2, 3, 3, 3 ; ventrals, 5, 5, 5, 5, 

 4 5i 6, 6, 5, 5, o, 5, 5, 6, 5, 4, 5. The most ventral setae in the ven- 

 tral fascicles the largest. Clitellum prominent, XI, XII, XIII. 

 Sexual papillae small, a large projectible penis, containing the pore of 

 a single large accessory gland. Septal glands IV to VI. Brain pos- 

 teriorly straight ; posteriorly much narrower than anteriorly. Dorsal 

 vessel rises in XVI. Intestine with chloragogen glands. Spermato- 

 phores present in the coelom. Spermatheca unusually enlarged, ex- 

 tending to X or XII ; not connected with the intestine, but terminating 

 in a closed ampulla ; the lower part of the spermatheca with two nar- 

 row diverticles. Sperm-funnels large ; sperm-ducts short, but very nar- 

 row; some eight small globular atrial glands opening into the atrium. 

 A single large accessory gland penetrating the penial bulb and open- 

 ing on a penial projection. Penial bulb contains several small globu- 

 lar glands opening near the pore. Nephridia with two large lobes. 

 Lymphocytes small, pointed, or oval. Color pale lemon yellow. 

 Blood deep orange yellow. 



Locality. Under decayed leaves and decaying bark of large 

 lupins, in the wash of the creek entering Laguna Pucrca, in San 

 Francisco, California. Adult only in November to January. 

 In February the sexual organs have completely degenerated. 



