POLYCMTA—BENHAM. 
73 
These worms agree with the account given by Rhlers 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 oi 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 
mutabilis, raised the question as to whether 0phryotrocha puerilis, Staurocephalus 
minimus Langerhans, and S. siberti McIntosh, 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 Staurocephalus 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 fiir wahrscheinlich, dass S. claparedi 
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 
