852 CONTRIBUTION TO AUSTRALIAN OLlGOCHiETA, II., 



It is rather noteworthy that the representative species of the 

 Phreodrilidse occurring in Australia fall definitely into two well 

 marked genera in distinction from the New Zealand, Kerguelen 

 Island, and South American species which are all placed in the 

 type-genus Phreodrilus. The Tasmanian form would seem, 

 further, to show closer affinities to the Australian genera than to 

 Phreodrilus, and it is of some value to note that one of the 

 characters which stands out as distinctive of Phreodriloides 

 and Astacopsidrilus against Phreodrilus, namely, the modifications 

 in connection with the spermathecal structures, is apparently also 

 noticeable in the Tasmanian representative. 



The posteriorly situated spermathecal apparatus so character- 

 istic of the Phreodrilidce and Lumbriculidce, I remarked in a 

 previous paper as being very unstable in the former family, and 

 this is apparently borne out in connection with that apparatus in 

 the present form. In Phreodriloides the spermathecal apparatus, 

 if represented at all, is denoted by the "autospermatheca"; in 

 Astacopsidrilus there is in one species a tendency towards fusion, 

 in another a complete fusion; and in both the ducts do not com- 

 municate with the exterior by means of a spermathecal pore; 

 in the Tasmanian representative the same structure is represented 

 apparently by a series of unpaired, non-connected chambers, and 

 no signs of a duct are visible. In all known species of Phreo- 

 drilus the spermathecal ducts and pores are distinct; and in all 

 probability that genus shows characters much closer to the 

 ancestral member of the family, and closer affinities to the 

 Lu?nbriculidce. The Australian and Tasmanian forms are then 

 to be regarded as specially aberrant forms, or otherwise as forms 

 representative of conditions of structure grading into that of the 

 Tubificidce, and which have possibly undergone some degradation, 

 that character being very probably associated with a change in 

 the position of the spermathecal apparatus towards a condition 

 characteristic of the earlier Oligochseta and of most existing 

 representatives of that group. The Tasmanian form would seem 

 to present the last phase of the spermathecal before their dis- 

 appearance, and to represent a condition intermediate between 

 the state of affairs in Astacopsidrilus and Phreodriloides. 



