CALIFORNIA ICI'Dnil.ID.i:. 45 



)liiig siiKill siij;;ir-l<)Mvus standing in a mw, willi llic I'lin-lilvc 

 iUTaiiged tubniai- cells between them (fig. J 20). In some sections a Imnch of nerve 

 fibers is seen on either side touching the papilla, connecting on the other hand with 

 the ventral ganglion. As to the natnre of (he pa[iilla Dr. Miclia'lsen snggests that a 

 somewhat similar <trgan in AcanthodrUus (jeorgvinus is a taste or " Wollust" organ, 

 ll is, however, not nidikely that the minnte light-refractive bodies are glandnlons. 



JNIany of the tnbular cells contain a line granulated secretion in varying (pian- 

 titics, which stain dark red with cosine. The fact that the whole papilla is concave in 

 the center speaks also strongly for the glandnlons natnre of the organ. The figure of 

 the ■' Augenapfela"'-like organ of Acanthodrilus, given by Michajlsen, may })0ssibly have 

 been taken from a young pa[)illa in which the glandulous bodies had not yet developed. 

 Organs of a somewhat similar nature have also been described by Horst from Ponto- 

 ^role.i: corefhriiriis 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- 

 chseta arc of an analogous nature. Among such organs would be included the tuber- 

 cnla pnbcrtatis, the puberty grooves, as well as some other epidermal structures in 

 Heliodrilns, 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. 



Se2}ta (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 ci'oss-section and this is also the case with the oviduct and the sperm- 

 sacs. This pouching is principally restricted to the septa 5 to 13. These septa are 

 also slightly thickened especially those bounding somites viii to xi. 



Nephridbt (figs. 59 to 77). The position of the iiephridio-pores places Argilo- 

 pliilus 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 sette. All the following open irregularly in front either of the 

 third or fourth set;e, 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, wdiile 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 f 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, etc. (Fig. 124 up. p.) 



Mkmoir;<, Vol. II, 3. Jauuary, ISU-l. 



