392 E. S. GOODRICH. 



Oder gelben Korpern, die in jedem Segmente und besonders in 

 den hintern liegen. Diese Stellen nun speichern auch das 

 Indigokarmin auf. Totet man mit Alkohol eine so bearbeitete 

 Nereide und spannt sie dann auf oder nimmt nur die Haut 

 der Riickenseite, so gewinnt man ein Praparat wo diese blauen 

 Organe in jedem Segmente sich metamerisch wilderholen und 

 den Eindruck besonderer regelmassiger Segmentarbildung 

 machen/' It seems evident that this excretory organ is not 

 the same as the dorsal organ I have described, which is not 

 glandular, and is not situated in the skin. Also Kowalevsky 

 makes no mention of cilia. On the other hand, it appears not 

 improbable that the "grosse AnhaufungenderBlutkorperchen" 

 seen below the excretory organ are the accumulations of 

 coelomic corpuscles, which seem to be collected together by the 

 cilia of the dorsal organ near the top of the outer limb 

 (PI. XXXIV, figs. 5, 7, coel. corp.) ; it also frequently happens 

 that a large number of ova are collected in this region. 



When I first discovered the dorsal ciliated organ in Nereis, 

 I was immediately struck with its remarkable resemblance to 

 the genital ducts (Geuitalschlauche) described in the Capitellids 

 in Dr. Eisig's beautiful monograph (6). I have obtained 

 sections of Nereis showing the organ in question almost exactly 

 like Eisig's figs. 1, 2, and 14, pi. xiv. It seems to me, there- 

 fore, very likely that we have here a " genital duct," which 

 has not yet acquired an opening to the exterior. My inability 

 to show such an opening may, perhaps_, be explained by the 

 fact that it has never been my good fortune to obtain a per- 

 fectly mature Nereid. The acquiring at maturity by the duct 

 of an opening would be a fact by no means unparalleled in 

 nature; in the Capitellids themselves it only occurs late (6). 

 It may be remarked, also, that the dorsal organ of Nereis and 

 the genital ducts of the Capitellids show many points of 

 resemblance in histological detail. 



Mr. Cunningham (4) argues that it would be quite impos- 

 sible for the genital products in Nereids to be discharged by 

 means of the nephridia ; in this I entirely agree with him. 

 Not only would it be impossible for the ova to escape by the 



