22'-i Gwynnefh Biuhanan : 



the oidinai-v coliuimar of non-glandular areas, and in among 

 the longtitudinal fibres (Fig. 3). 



Accessory copulatory structures are common among Oli- 

 gochaetes, being called by various names, and Fletcher describes 

 theii- external appearance in C. sdccarins^^ but I have not found 

 tlieii- minute structure mentioned elsewhere. Spencer'^ points out 

 a large development of glandular cells in the clitellar region of 

 Megascolides australis, evidently similar in histological struc-' 

 ture to those of the accessory glands in C. saccarius, but dif- 

 fering in not being grouped to form separate organs. He also 

 notes the penetration of the epidermis by fibres, but describes 

 the epidermal cells as being shorter than elsewhere, while in 

 C. .saccarius they are longer around the glandular patch. It 

 is evident that the function of these secreting cells in the 

 clitellar region is connected with the formation of the cocoon ; 

 the fact of their being collected into patches around the genital 

 openings, however, seems to point to their function here being 

 principally to secrete mucus, which would aid in the passage 

 of the reproductive elements to the cocoon and of the body of 

 the worm through it without friction. 



Since going to press I. tind that a very similar set of accessory 

 structures has been described and figured by Miss G. Sweet 

 (Linn. Soc. Journ. Zool., vol. xxviii.) in Digaster excavata and 

 Jfegascolex dor satis. 



EXPLANATION OF PLATE XLIIL 



Fig. 1. — External appearance of an accessory gland of C. 

 saccarius between segments 12 and 13. 



Fig. 2. — The same around the male opening, segment 18. 



Fig. 3. — Low power drawing of the accessory glands and 

 associated structures between segments 12 and 13 in 

 C. saccarius. (Outline with camera lucida). 



1 I'l...-. Linn. Soc. N.S.W., 1889. 



1 Transactions of Koy. Soc. Vict., vol. i., pt. i., 1SS8. Tiie Anatomy of Mejia.scolidc! 

 aiistralis. 



