336 AUSTRALIAN HIRUDINEA, I., 



outwards to the testes. From here no further traces of the male 

 ducts can be found. Unlike other species of Glossiphonia there 

 are no winding vasa deferentia in the median lacuna, and there 

 appears to be a connection between the genital ducts and the 

 digestive tube. 



Nervous system. — As in all species of Glossiphonia there are 

 twenty-one ganglia in the ventral nerve-chain. In connection 

 with the constitution of the brain, I have been able to make out, 

 from the study of the nerve-capsules, that the brain is composed 

 of six fused ganglia. Oka has stated that he finds in the brain 

 of Glossiphonia always thirty capsules, and he comes to the con- 

 clusion that it represents five fused ganglia. My conclusions are 

 in accord with those of Whitman and Castle. As Castle has 

 pointed out, Oka has possibly overlooked altogether the capsules of 

 somite i., which lie anterior to the supra-oesophageal commissure. 

 The posterior ganglionic mass represents seven fused ganglia. 



Owing to the excellent work of Whitman, Castle, and Oka on 

 the metameric constitution and ganglionic structure I cannot 

 add anything of special interest in connection with the structure 

 of the nervous system. 



From the study of the nervous system it is seen that the body 

 consists of thirty-four metameres, twenty-one of which are repre- 

 sented by the distinct ganglia of the ventral nerve-cord. 



Nephridia. — These are very much reduced and inconspicuous, 

 structures, No traces of the nephridial funnels have been seen 

 in section, and no well marked nephridiopores. The exact 

 number of nephridia I have been unable to determine; and I can 

 find no mention of the number in connection with the closely 

 allied species, Glossiphonia heleroclita. 



Castle mentions in his account of the Fresh-water Rhyn- 

 chobdellids of North America the number of nephridia in all 

 the species except in G. heteroclita. Unfortunately I am not in 

 possession of specimens of this species, and so cannot at present 

 make any comparative remarks. 



Oka and Bourne have written a good deal in connection with 

 the nephridia in general, and I find in this species differences 



