134 CALIFORNIA ACADEMY OF SCIENCES. 
Spermducts are considerably thickened, but the lower part is not any thicker 
than the upper part, as in B. nana. 
Gonads are affixed high up on the septum and not at the junction with septum 
and body-wall. 
Prostates. These bodies are larger than in B. nana, but nevertheless generally 
confined to one somite each. The penial sete are, as usual, of unequal size. The 
larger seta is furnished with four notches, the smaller is spoon-like and forked at the 
apex. 
Nephridia. These organs are arranged in three distinct rows on either side of 
the median line, but the nephridia in each somite are of unequal size. The nephri- 
dium nearest the ventral ganglion or nephridium a consists of two, more or less, 
separate parts, evidently a tendency to diffusion or an imperfect centralization. The 
most ventral part is the smallest and the most distal the largest. The ducts run con- 
tinuously between these parts, but the ecelomic cells are grouped in such a way that 
the bridges between the two parts are quite narrow. The nephrostome of nephridium 
a was always plain and readily seen, but I never succeeded in finding the nephro- 
stomes of bande. Still, these nephridia appear perfectly formed on the meganephric 
principle, and I could never see any connection by canals between @ and /, and } and 
c, though sometimes the ccelomie cell masses extended more or less continuously over 
and between the respective nephridia a, } and ce. 
Nephridia @ open in front of setee 1 and 2, while in B. nana they open in front 
of 5and 4. ‘The most anterior nephridium possessing a coelomic covering I found in 
xxi. Through the courtesy of Dr. Michaelsen, I have received specimens of J. 
Bolavi for comparison. The nephridium of Bb. palmicola resemble that of 6. Bolavi, 
but is much larger, and the respective nephridia cover each other slightly, while in 
the two specimens of 4. Bolavi which I dissected the respective nephridia were sep- 
arated by considerable distance; the latter nephridia are also smaller. I had at first 
intended to assign these species of Benhamia possessing several nephridia of a perfect 
form under a separate subgenus, when my attention was called to the fact, by Dr. 
Michaelsen, that B. Stuh/manni sometimes possessed a similar arrangement of nephri- 
dia as those in B. Bolavi, ete. As the nephridia of B. Stuhimanni are generally 
plectonephrie or diffuse, it became at once evident that this distinction could not be 
used as a generic character of value, and that it really is impossible to draw any dis- 
tinct line between a plectonephric and a micronephric condition. It is, however, en- 
tirely incorrect to characterize these nephridia as a mass of tubules, etc., as wherever 
they are separated one from the other, as in Bolavi, palmicola, nana, rugosa and 
probably great many other species, each micronephridium is perfect in itself, and built 
on the same general principle as the meganephridia of the other terricole. I would 
therefore propose to. make a distinction between plectouephidia, or really diffuse 
nephridia, and micronephridia, or nephridia of small size, but perfect, or built on the 
meganephric plan. Such a distinction may be useful in descriptions, even if they are 
not morphologically distinct. 
