ANNELID GENUS CAMBARINCOLA — HOFFMAN 313 



Diagnosis. — A large species of the Macrocephala group with a 

 broad, enlarged head, tentaciilate peristomiuin, isomorphic and 

 similar jaws, large globose bursa, very long cjaculatory duct, long 

 reflexed spcrmiducal gland wdth large symmetrically disposed ental 

 deferent lobes, and an equally large reflexed prostate gland, extending 

 ventrad to the level of the deferent lobes. 



Description. — Maximum size of preserved worms, 4.8 mm. in 

 length, 0.8 mm. in diameter at segment vii, and 1.1 mm. in greatest 

 head width. Body outlme of the usual profile, increasing in diameter 

 up to segment vi, thereafter decreasing more abruptly to the penulti- 

 mate segment. 



Body segments very short m proportion to their diameter, the 

 ratio about 4/1 to 5/1 ; prosomites about twice as long as metasomites 

 and of slightly greater diameter. 



Head very large, as long as the first five body segments combined 

 (the entu-e anterior half of the body) , its diameter as great as that of the 

 broadest body segment. Peristomium not set off by a basal constric- 

 tion nor strongly flared (at least in the material at hand), but divided 

 into dorsal and ventral halves, the dorsal provided with four distinct 

 slender submarginal tentacles, the ventral broadly bilobed. 



Jaws large and robust, very similar in both size and shape, the dental 

 formula 3-3; both jaws much wider than their length. 



Male reproductive system large, occupymg one entire side of the 

 coelom of segment vi and extending mesad to the midventral and 

 middorsal areas. Bursa very large and globose, as broad as long, the 

 penial sheath occup3dng the ental half and normal in structure for 

 the genus. Ejaculatory duct very long, extending dorsolaterad 

 around the gut and somewhat dorsomesad to the junction of spcrmi- 

 ducal and prostate glands. Both of the latter are then reflexed 

 ventrad, curving around the gut do\vn to the level of the penial 

 sheath, where the spermiducal gland is evenly divided into two very 

 similar deferent lobes which proceed ventromesad around the bursa 

 to merge with the deferent ducts. Prostate similar in length and 

 diameter to spermiducal gland, entally it is broadly rounded and 

 completely overlaps the caudal deferent lobe. 



Variation. — The available material from Idaho is quite homo- 

 geneous and presents only the size variation that one would expect 

 in a single collection. 



The holotype of macrocephala, mounted flat on a slide, differs 

 somewhat from the specunens described in that the peristomium is 

 set off by a basal constriction, with the tentacles somewhat smaller 

 both in length and diameter. These differences may be due to preser- 

 vation in strong alcohol. On the other hand, some of the anterior 

 segments of the type specimen, notably from iii through vi, are quite 



