110 DR. J. STEPHENSON ON THE MORPHOLOGY, CLASSIFICATION, 



the name of my former colleague, Prof. Shiv Ram Kashyap of 

 Lahore. 



Diagnosis : — Seta? eight per segment. Male pores on xviii. ; 

 two pairs of prostatic pores, on xvii. and xix. Spermathecal 

 pores two pairs, in 7/8 and 8/9, or on viii. and ix. Gizzard in 

 vi. All septa present after their commencement. No calciferons 

 glands. Micronephridia; micronephridia relatively large, few 

 in number. Testes and funnels free in x. and xi. 



Distribution :— India (Mahableshwar, S. Rajputana, Saharan- 

 pur). 



It will be noted that the species extend in a line from the 

 Western Ghats to the Western Himalayas, the most primitive 

 (at least the one in which the reduction in the number of 

 nephridia has made least progress) being at the southern end, 

 the most modified at the northern. 



The relationships of the genera of Octochaatinaa may be set 

 forth in the accompanying tree: — 



" Original Acanthodviline." 

 (Hoivascolex ?). 



Octochcetus. Tloploclicetella. Ramiella. 



Dinodrilus. JSidyphceus. I Eudichogaster. 



THrythrceodrilus. 



(On the question of the inclusion of Howascolex in the ancestral 

 line of the Octochsetinae see (8), and the references there given. 

 On the inclusion of Hoplochcetella and Erythrceodrilus in the 

 Octochaatinos see (10).) 



Probably no genealogical tree expresses relationships with 

 exactitude; every genus is strictly speaking at the end of a 

 short side line. Thus Ramiella probably comes off the main 

 stem shortly above the position of Howascolex ; the original 

 meganephridium seems to have broken up in a different way in 

 these two genera — in Howascolex to have become one still fairly 

 large and a number of minute nephridia, in Ramiella to have 

 dissolved into a few moderate-sized organs. 



The Derivation of the genus Diehogaster. 



There remains the question of the origin of the genus 

 Diehogaster. In 1903 and 1909 Michaelsen regarded it as 

 derived from Eudichogaster ; while in 1910 he states that 

 morphologically it is best derived from Eudichogaster, though 

 geographically it would appear easier to derive it from Trigaster; 

 the geographical argument is, however, not by any means 

 absolutely cogent — there is nothing in the facts essentially 

 opposed to the derivation from Etulichogaster. 



To this view of the origin of Diehogaster I cannot agree. In 



