POLYCH^ETA BEJSfHAM. 73 



These worms agree with, the account given by Ehlers of his species, which was 

 founded on a single specimen. In his later memoir, however, he had a good number 

 of individuals at his disposal, and he notes certain variations presented by them, such 

 as the presence or absence of eyes, details in the form of the jaw apparatus, &c. 



The species differs from the northern 0. puerilis Claparede and Metschnikoff, in 

 the absence ot the ventral tentacles on the prostomium, and in the absence of the 

 median anal cirrus, as well as in other details. 



As long ago as 1888 De St. Joseph (p. 240), in describing the species Paractius 

 mutdbilis, raised the question as to whether Ophryotrocha puerilis, Staurocepkalus 

 minimus Langerhans, and S. siberti Mclntosh, should not be ranged under the generic 

 name Paractius Levinsen ; though it would have more in accordance with the usual 

 practice to include the latter under the earlier title. In 1895 (p. 210) he returns 

 to the question, and records his belief that Claparede's species is distinct from 

 P. mutabilis. 



Later, Bonnier (1893), in discussing Studer's species, notes that his account is 

 '" malheureusement insuffisant" owing to the fact that the material had been lost after 

 the preliminary account had been drawn up. Bonnier suggests that it is probably a 

 synonym of 0. puerilis. He then considers the validity of Levinsen's genus, and 

 concludes that it and the abovenamed species of Staurocepfialus are all referable to the 

 genus Ophryotrocha. In that work will be found a complete bibliography up to that 

 date. 



In the same year Korschelt went into the question, chiefly in reference to the 

 jaws in the Mediterranean species, and arrived at a similar conclusion. 



Ehlers ( 1908) makes no reference to this discussion, but does so in his later memoir, 

 and seems to agree with the conclusions arrived at by Bonnier. Although he retains 

 the title Paractius notialis at the head of his account of the worm, he discards it at the 

 end ; for he writes "nach dem alien halte ich es fur wahrscheinlich, dass S. daparedi 

 und P. notialis identisch sind,' ' and in all probability are to be assigned to the species 

 0. puerilis, which would thus be a highly variable cosmopolitan species. 



The only point that remains for solution is the question as to whether Studer's 

 antarctic species is or is not identical with the northern form. 



With the abundant material in my possession, I hoped to look into the question 

 more thoroughly, but this Report has already been delayed by the calls on my time 

 for University work, that this matter must for the present remain open. I hope, 

 however, to look into it later, especially to see whether the jaw apparatus presents any 

 constant differences from that of 0. puerilis. 



Locality. 



Boat^Harbour. 



Distribution.- Kerguelen (Studer, Ehlers), K. Wilhelm-II Land (Ehlers). 



83892 K 



