444 



J 11. FIXLARTON. 



List ol' Reference Letters. 



nerve cells. 



ganglion of ventral chord. 



network of fin. 



ventral nerve chord. 



lateral nerve. 



ovary. 



ovum. 



ovarian cells in ovary. 



mass of free ovarian cells. 



pellicle. 



parapodium. 



lobe of parapodium. 



polar body. 



protoplasm. 



rosette-like organ. 



spermatozoa. 



testis. 



testicular cells. 



vacuole. 



vesicula seminalis. 



inner opening of same. 



outer of opening of same. 



Fig. 1. One of the lobes of a parapodium and fin-like expansion 

 of a ripe male .showing the testis in its cavity. Zkiss Oc. 8, Ajjo. 

 8 mm. (The drawing is combined from a stained pre])aration and, the 

 fin-like expansion, from an osmic acid specimen.) 



Fig. 2. Transverse section of a lobe of a parapodium of a young 

 male showing the male genital cells arising from the endothelium. 

 Zeiss Oc. 8, Apo. 8 mm. 



Fig. H. Similar section of a rij^o male witli genital cells increased 

 in number. Zki.ss Oc. 8, Apo. 8 mm. 



