278 F. M. Turnhull — Anatomy and Habits of Nereis virens. 



The sense-organs are the four eyes, the four antennte, the tentacular 

 cirri, and the dorsal and ventral cirri of tlie feet ; also the long slender 

 cirri of the posterior extremity. The antenna- and cirri are organs of 

 touch. 



Organs of Reproduction. 



The sexes are separate, and the genital organs appear as simple 

 glandular bodies, ovaries or spermaries, which project from the ven- 

 tral sLiiface into the cavity of the body, between the transverse mus- 

 cular partitions. At the sexual period they are tilled with eggs or 

 spermatic particles, although at other times they can scarcely be seen. 

 Neither the spermaries nor the ovaries have special excretory ducts, 

 which open upon the surface of the body. The sperm and ova are 

 discharged into the cavity of the body, wdiich at this period is often 

 filled with them. At the base of the lower ramus of each foot (fig. 22, 

 g) is a glandular body, called the segmental organs. Some of these 

 are normally kidneys, as ui-ea has been found in them, but some are 

 usxxally modified to act as oviducts, having a trumpet-shaped mouth 

 opening into the body cavity and communicating with the exterior. 

 I found the segmental organs all along the body beyond the region of 

 the proboscis, but was unable to find the trumpet-shaped tubes. 

 These are probably situated in the posterior segments, as Professor 

 Verrill has seen the male worms discharging their milt from that 

 portion of the body. The fecundation takes 2:)lace in the water. 



EXPLANATION OF PLATES. 

 Plate XLII. 



Figure 1. — Nereis virens, female; dorsal view of the anterior portion of the body; a, 

 head, with four eyes ; 6, h, antennte ; c, c, palpi ; c', c', lobes of palpi ; cZ, buccal 

 ring ; ee, ee, longer dorsal pair of tentacular cirri ; ee', ee', shorter dorsal pair of 

 tentacular cirri ; e, e, longer ventral pair of tentacular cirri ; e', e', shorter ventral 

 pair of tentacular cirri; h, lateral appendages; g, abdominal rings. 



Fig. 2 and 2a. — Two forms of setaj; a, shaft; h, blade. 



Pig_ 3. — First lateral appendage of female, posterior view ; lettering the same as in 

 fig. 8. 



Fig. 4. — Second lateral appendage of female, posterior view ; lettering the same as in 

 fig. 8. 



-pig, 5. — Third lateral appendage of female, posterior view ; lettering the same as in 

 fig. 8. 



Pig_ 6. — Fourth lateral appendage of female, posterior view ; lettering the same as in 

 fig. 8. 



Pig. 7. — Fifth lateral appendage of female, posterior view ; lettering the same as in 



