CALIFORNIA EUDRILIDA. 15 
regular, the former resembling small sugar-loaves standing in a row, with the fan-like 
arranged tubular cells between them (fig. 120). In some sections a bunch of nerve 
fibers is seen on either side touching the papilla, connecting on the other hand with 
the ventral ganglion. As to the nature of the papilla Dr. Michelsen suggests that a 
somewhat similar organ in Acanthodrilus georgianus is a taste or * Wollust”? organ. 
It is, however, not unlikely that the minute light-refractive bodies are glandulous. 
Many of the tubular cells contain a fine granulated secretion in yarying quan- 
tities, which stain dark red with eosine. The fact that the whole papilla is concave in 
the center speaks also strongly for the glandulous nature of the organ. The figure of 
the “Augenapfela”-lke organ of Acanthodrilus, given by Michelsen, may possibly have 
been taken from a young papilla in which the glandulous bodies had not yet developed. 
Organs of a somewhat similar nature have also been described by Horst from Ponfo- 
scolex corethrurus which, however, he does not figure in connection with nerve fibres, 
It is not improbable that all the sensory organs in the genital somites of the higher Oligo- 
chieta are of an analogous nature. Among such organs would be included the tuber- 
cula pubertatis, the puberty grooves, as well as some other epidermal structures in 
Heliodrilus, Hyperiodrilus and Eudrilus described more in detail by Beddard. How- 
ever all the organs require re-examination by the aid of other methods, as one single 
method of staining will not suffice to reveal their true nature. 
Septa (fig. 86). The anterior septa are greatly pouched, generally to such 
an extent that in cross-sections the various organs appear to lie several somites further 
back than they really do. Thus the gizzard and the posterior spermatheca may be 
seen in the same cross-section and this is also the case with the oviduct and the sperm- 
sacs. This pouching is principally restricted to the septa 5 to 15. These septa are 
also slightly thickened especially those bounding somites viii to xi. 
Nephridia (figs. 59 to 77). The position of the nephridio-pores places Argilo- 
philus very close to Plutellus. There are one pair of nephridia in each somite as usual. 
The first pair of nephridia are found in somite ii and others follow in all the posterior 
somites. The first five or six nephridia are somewhat larger than the others and open 
in front of the fourth sete. All the following open irregularly in front either of the 
third or fourth sete, or in the space between and anterior to them, or even outside of, 
or more lateral than seta four. Those which open laterally of seta four do not even 
open in the same row, as we find one nephridio-pore say as far out laterally from 
the fourth seta, as that seta is distant from the third, while others are half-way or one- 
third of the way between the fourth seta and the most lateral nephridio-pore. There 
is no regularity as regards this succession, though rarely two successive nephridia open 
in line behind each other. For instance, one nephridium opens in front of seta 
3; the second as far outside of 4 as 4 is distant from 3; the third nephridio-pore is 
in front of seta 4, the following half-way between seta 4 and the most lateral pore, 
the following % of the distance from seta 4 to the most lateral pore, the following in 
front of seta 4, the following again % of the distance from seta 4 to the most lateral 
nephidio-pore, ete. (Fig. 124 np. p.) 
Memoirs, Vou. II, 3. January, 1894. 
