56 



CALIFORNIA ACADEMY OF SCIENCES. 



than likely that ii mistake was made, as Benham has already pointed out. But on the 

 other hand Benhara's worm came from Queen Charlotte's Islands in the Pacific, while 

 Perrier's worm came from the Atlantic Coast, many thousand miles away, and it will 

 always be impossible to with certainty decide upon the position of the ovaries in 

 Perrier's Plutellus until the original worm has again been investigated. That it will 

 be found to entirely agree with the normal type I do not doubt. 



From Plutellus our Argilophilus differs in several important jioints besides the 

 location of the nephridio-pores. First, in regard to the number of the ciliated rosettes — 

 in Plutellus only one pair, in Argilophilus two jjair. One pair of sperm-sacs in Plu- 

 tellus, three pair in Argilophilus. One pair of testes in Plutellus, two pair in Argilo- 

 philus. Four pair of small spermatheca in Plutellus, two very large ones in Argilophilus. 

 Perfect clitellum in Plutellus in at least two somites, ventrally imperfect clitellum in 

 Argilophilus. In other respects the two genera resemble each other greatly, and 

 through the respective arrangement of the nephridio-pores, they form a distinct tribe 

 or sul)-family foi' which I propose the name P/uicliuiL 



The following table will show the principal characteristics of the two genera: 



Proslomiiim dovetailing the peri- 

 stouium 



('/ill Hum 



Niphridio-pores. 



Gizzard iu . . 

 Spermathern 



SpiTm-funuel 

 Tenli's 



Ovfinj .iiul oriiinri ill 



Or} pore in 



Male pore in 



Prostate 



Niphridia commence in . 



Nephridial bladder at the entrance 

 ti) the body- wall 



Ventral pn/i/llie on the bodj'-wall, 

 ( 'o/iiilalori/ xeia' 



Typhlosole. 



Argilophilus. 



Partly. 



Ventrally imjierfect. 



In front of setaa 3, 4, and outside of 4; gen- 

 erally the latter, the anaugement being 

 in-egular. 



Two very larf;e pair iu vii and viii. 



Two pair in x and xi. 



Two pair in x and xi. 



Three pair iu x, xi, xii. 



xiii. 



xiv. 



xviii. 



Very large, coiled, extending through several 

 somites. 



Absent, the duct being single and straight. 



Present iu pairs or in a single one. 



Present. 



A small typhlosole present. 



Plulellns. 



Completely. 



Ventrally perfect in at least two 

 somites. 



In front of 3 and 4, alternating 

 rather regularlj-. 



Four or five pair in vi, vii, viii 

 and ix. 



One pair in x. 



One pair in x. 



One pair in xi. 



xiii. 



xiv. 



xviii. 



Straight, tubular, not very large, 

 confined to oue somite. 



Large, but of varying size in the 

 two series of nephridia. 



Absent. 



Absent. 



No typhlosole. 



