122 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D See. 



greatly varying in size. In some specimens the glandular part is only knob- 

 like, while in others it is much longer and folded, but does not extend 

 beyond somite XIX. Meganephridia very large, as wide as the somites, 

 the posterior ones with ccelomic mantle. 



Habitat. — This species is abundant in the valley of 

 Comondu in the central part of Baja California, Mexico. 

 It is the only Ocnerodrilide found there in the irrigation 

 ditches and in wet soil generally. Collected June 25, 1899. 



Characteristics. — The absence of setae ab in XVII and 

 the undulating margins of the setae bring O. comondui near 

 to O. Hendriei, from which it differs in having the sperm- 

 sacs in somite IX strongly racemose, and in the form of the 

 spermathecae and the sizes of the respective septal glands. 



The difference between O. comondui and O. santi xavieri 

 is in the undulating margins of the former and in the nephri- 

 dia, which are relatively larger than those in the latter 

 form, as may be seen by examining the specimens exte- 

 riorly. It is also a larger and especially a thicker worm. 



The septal formula, differing from that of O. santi 

 xavieri, is as follows : — 



IV/V, V/VI, VI/VII, VII/VIII, VIII/IX, IX/X, 



X/XI, XI/XII, XII/XIII. 



sperm-sacs. — The racemose sperm-sacs in IX do not 

 project from the septum forwards, but spring from the body- 

 wall a little in front of the septum on the dorsal side of the 

 body. This is also the case in Ocnerodrilus santi xavieri, 

 and perhaps in other species. 



The sperm-ducts open in the same pore as the prostates, 

 but do not enter them. 



The prostates vary more in size than in any other species so 

 far known. In some specimens the glandular part consists 

 merely of a knob-like body, while in others the glandular 

 part is several times as long as the muscular part and 

 extends through somites XVII and XVIII. But as I could 

 see no other differences, both these forms are for the pres- 

 ent referred to one species. 



No ovisacs are present. 



