CALIFOKNTA KirOUIMD.K. 55 



No. 2. One piiir, ix/x. 



One single, xv/xvi, loft side. 

 No. 3. One pair, ix/x. 



One pair, x/xi. 



One single, xiv/xv, right side. 



One pair, xv/xvi. 



One pair, xvi/xvii. 



One pair, xx/xxi. 



One pair, xxi/xxii. 

 No. 4. One pair, x/xi. 



One pair, xv/xvi. 



One pair, xix/xx. 

 No. 5. One pair, x/xi. 



One pair, xix/xx. 



The strneture of these papilhe has been referred to in connection witii the 

 hody-wall, and apparently does not dift'er in the two forms. 



Argilophilus marmoratus papillifer. 

 Fig. 131, Aand-B. 



Argi/ojjhilus marmoratuf^ papUllfer Eiseu, Zoe, iv, 253, October, 1803. 



The ventral side of the somites with one single median row of ventral pa[)illiie, 

 which are generally largest between the clitellar somites, diminishing gradually in 

 size toward the anterior somites. The papilhe of this form are generally, but not al- 

 ways, more oblong than in the preceding form, vvhere they are much more rounded. 

 The clitellar papilla^ are frcfpiently diamond-shaped (fig. 131). The papilla' vai'y 

 greatly in number and size in various individuals, but they are always median, never 

 paired. Sometimes there are G to 7 papillae posterior of the clitellum. 



Habitat. This worm is very common in the vicinity of San Francisco Bay, 

 south of Santa Rosa, where the former form begins. I have also this form from Santa 

 Clara County, Monterey County, Fresno County, etc. It is common in the foothills 

 of the Sierra Nevada, in Nevada County. Among many hundred sjiecimens col- 

 lected there was ©nly one which possessed the paired papilhe of the former form. 



Systematir. 'positinn. The peculiar variation of the nephridio-pores places 

 Argilophilus in undoubted proximity to Plutellus, both as described by Perrier and 

 Benham. The extra chtetal pores in Argilophilus warrants however the forma- 

 tion of a new genus, even if no other important characteristics would help to make it 

 yet more distinct. As is well-known, Perrier's description of the ovaries, etc., in 

 Plutellus have always been considered doubtful, and by Benham have been shown to 

 be incorrect. This of course only in the case that Benham's worm really belongs to 

 the same genus as the one described by Perrier. I do not douI)t that this is so, be- 

 cause the positions assigned to the ovaries by Perrier is so al)nornial that it is more 



