444 WILHELM MIOHAELSEN. 



Prof. Jagerskiold, Director of the Grotenborg' Museum, 

 kindly lent to me the t3'pe-specimen for re-examination, and 

 I am thereby enabled to make a certain correction to my 

 former description. 



In the original description it is said that segments 4-10 are 

 all divided into two ringlets ; but this is a slip, only the fourth 

 to the ninth segments are biannulated. To a specialist this 

 was evident from the statement that the hinder ringlet of the 

 ninth segment was very much shorter than the front ringlet. 

 This great difference between the lengths of the ringlets 

 always occurs in the last of the biannulated segments. 



The main difference in the anatomy of this species and M . 

 colletti Bedd. is the shape of the sexual setfe. In coUetti 

 they are distinctly S-shaped, while in M. gracilis they are 

 quite straight for nearly the whole length, and are only very 

 slightly curved at the distal end. They are not provided 

 with a distinct nodulus ; also the elements of ornamentation 

 consist of deep longitudinal scars. 



The shape of the copulatory walls is also different in 

 gracilis and colletti. 



Microchtetus ivari Mich. 



Microchsetiis ivari Michaehen, " Oligochaiteu von Natal dem Zuln- 

 lancl." Arkiv. Zool., iv. nr. 4. p. 10, Text-fig. 4. 1907. 



Hab. — Estcourt, Natal (teste Michaelsen). 



I examined the type-specimen and found it in a worthless 

 condition, and we must therefore rely on the original descrip- 

 tion. 



This species differs from the nearly allied M., colletti 

 Bedd. and M. gracilis Mich, by the shape of the copulatory 

 walls, by the position of the copulatory papillae (on the 

 twenty-first segment), and chiefly by some points in the 

 internal anatomy. 



The sexual seta? resemble genei-ally those of M. gracilis, 

 but differ in the character of the ornamentation. 



Finally, M. ivari differs froin both of its allies in the 



