56 CALIFORNIA ACADEMY OF SCIENCES. 
than likely that a mistake was made, as Benham has already pointed out. But on the 
other hand Benham’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 points 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 pair. One pair of sperm-saes 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 sub-family for which I propose the name P/lute/lini. 
The following table will show the principal characteristics of the two genera: 
| 
> % | 
Argilophilus. Plutellus. 
Prostomium dovetailing the peri- 
BUODAUIN  osayay- qricversitereteaeleletake set | Partly. Completely. 
(CLUPICUITE rete ogd DOS OOOO COI ACTA Ventrally imperfect. Ventrally perfect in at least two 
somites. 
Nephridio-pores..............-...|In front of sete 3, 4, and outside of 4; gen-| In front of 3 and 4, alternating 
erally the latter, the arrangement being) rather regularly. 
irregular. 
Qagzard tie Ree nc oe any senate Vv. vi. 
Spermatheca ........+...+........| Two very large pair in vii and viii. Four or five pair in vi, vii, viii 
and ix. 
SPERMAPUMMEU casei ase cies hetero Two pair in x and xi. One pair in x. 
Tegteg tee sate Salgceeh Manatee se Two pair in x and xi. One pair in x. 
SYMP UREN 26 o.oo clbbouco tecdenigeys Three pair in x, xi, xii. One pair in xi. ° 
1 
Ovary and oviductin ........... | xii. xiii. 
Owipore lay J.cacsncines torch | xiv. | xiv. 
| 
Maile por erin my ctocetes sents Xvill. | xviii. 
Prostate Very large, coiled, extending through several Straight, tubular, not very large, 
somites. confined to one somite. 
Nephridia commence in.......... ii. ili. 
| 
Nephridial bladder at the entrance Absent, the duct being single and straight. | Large, but of varying size in the 
to the body-wall. . 2. .ccsee ae | two series of nephridia. 
Ventral papille on the body-wall.| Present in pairs or in a single one, | Absent. 
Present. Absent. 
Copulatory seta 
Typhlosole. senses. esses...) A small typhlosole present. No typhlosole. 
