ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 379 



directed to the peculiar brown bodies found near the " bell margin," 

 which seem to be characteristic, and to the ventral nerve-cords which 

 have never yet been represented. 



12. Capitella. 13. Lumhriconereis. The jaws of this larva, when 

 simplest, have a remote resemblance to the chitinous teeth of 

 BrancMohdella astaci. 



14. Nectonema agilis[e]. Some observations are made on this 

 worm, the affinities of which are, as Verrill suggests, probably with 

 the Nematoidea. 



Excretory Apparatus of Hirudinea.* — F. Vejdovsky gives some 

 new facts respecting the segmental organs of leeches ; these organs 

 consist of a terminal vesicle into which opens a simple duct connected 

 at its dorsal extremity with a gland consisting of a number of large cells 

 traversed by a winding branched duct. In Glepsine hioculata and other 

 species the central duct of the glandular portion of the organ breaks 

 up here and there into a fine network. The whole of the segmental 

 organ which has no cilia is surrounded by a rich network of blood 

 capillaries in Hirudo medicinalis and Aulostoma gulo ; in Nephelis and 

 other genera this vascular sheath is entirely wanting. The segmental 

 organs of the Hirudinea resemble those of Chcetogasfer more closely 

 than any other form ; in neither is there a ciliated funnel or cilia 

 developed along the course of the duct ; the glandular portion of the 

 organs is, however, but slightly represented in Chcetogaster, and it is not 

 known whether the duct is branched in this region. Both these fami- 

 lies are degenerate Oligochaeta, and the segmental organs are evidently 

 traceable to the type found in Oligochseta and have no connection what- 

 ever with those of Gunda and other Planarians ; the branched ducts 

 of the latter are not comparable to the fine ramifications in the leech's 

 segmental organs, since they are provided with independent walls, 

 while the ramifications of the central duct of the nephridium in the 

 Hirudinea are contained within the substance of the glandular cells 

 themselves. An additional proof of the direct relation between the 

 segmental organs of the Hirudinea and the Oligochaeta is to be found 

 in the close similarity of the development. 



Function of Pigment of Hirudinea.t — E. Saint-Loup finds that 

 when a young NepTielis has been eating, the three hinder portions of the 

 four into which its intestine may be divided are covered on their surface 

 with small yellowish-brown granulations which gradually become 

 closely packed ; they are arranged on the walls of the capillaries 

 which, clearly, carry to the blood the digested food. In the adult the 

 tunic of yellowish-brown spherules lies on the inner face of the 

 musculo-cutaneous layer, but remains in relation to the intestine by 

 means of the fine vessels which invest its walls. The author has been 

 able to demonstrate the continuity between the yellowish spherules 

 and the pigment-granules, and there appears to be in the Hirudinea 

 a special excretory or pigmentary function in these yellowish-brown 

 cells. A further question arises on the relations which exist between 



* SB. K. Bohm. Gesell. Wiss., 1883, pp. 273-80 (1 pi.), 

 t Oomptes Rendus, xcviii. (1884) pp. 441-4. 



