302 J. H. ASHWORTH. 



9. These organs are similar to those described by Eisig in 

 the Capitellidte, except that in the latter there are no large 

 ganglion cells beneath the rods. The sense organ is not^ as 

 Eisig supposed, morphologically equivalent to a neuropodial 

 dorsal cirrus. It does not form part of the neuropodium ; it 

 occupies a position between the two parapodial rami, but it 

 may be connected by means of its retractor muscle to the 

 base of the notopodial setal sac. Eisig believes that the 

 sense organ is homologous with the dorsal cirrus of the 

 Glyceridae, and that the parapodium of Gycerids is a neuro- 

 podium only (the notopodium being absent) equivalent to the 

 neuropodium of Capitellidae. This view cannot be supported • 

 the parapodium of the Glyceridee is essentially biramous, its 

 division into notopodium and neuropodium being less obvious 

 than in many Polych^etes, owing to the close approximation 

 of the two rami. (For further details of the discussion 

 see p. 276.) 



10. Each nephridium is a delicate ciliated tube opening 

 into the coelom by a minute simple nephrostome. The ex- 

 cretory part of the tube is bent once upon itself. There is a 

 pair of nephridia in each chsetigerous segment except the 

 first three. 



11. Scalibregma inflatum is dioecious, and not herma- 

 phrodite, as described by Danielssen. The gonads are formed 

 by proliferation of the cells covering the septum by which 

 the nephrostome is attached to the body- wall. The genital 

 cells fall from the gonad at a very early stage, and complete 

 their growth in the ccelomic fluid. In their structure and 

 stages of growth the ova and spermatozoa closely resemble 

 those of Arenicola. Eumenia crassa and Lipobran- 

 chius jeffreysii are also dioecious, and their genital pro- 

 ducts are similar to those of Scalibregma. 



12. The prostomium is an important character in the 

 classification of the Scalibregmidge. It affords, along with 

 the nature of the parapodia, the most reliable means of deter- 

 mining whether a given specimen belongs to the Seal 

 bregma — or to the Eumenia — section of the family. 



