1897 - 98 .] Prof. D’Arcy W. Thompson on Marine Faunas. 323 
internal characters enabled me to refer the specimen to the genus 
Drepanophorus (the transverse coeca of the proboscidean sheath 
being in this case the guiding feature). The systematic position of 
this specimen thus only rests upon the similarity of the transverse 
sections and on the general yellow hue of the fragment, darker on 
the dorsal than on the ventral surface ” (Rep., p. 18). While 
such evidence was no doubt reasonably valid as grounds for treat- 
ing together the several fragments of the worm, I cannot imagine 
that it will really be relied upon as evidence of specific identity 
between the nemertine faunas of the northern and southern seas. 
Burger (Fauna and FI. des GoJfes y. Neapel, Nemertinen, p. 
572), including D. serraticollis (as Hubrecht had already suggested 
might be necessary) in D. (Cerebratulus) crassus of Quatrefages, 
adduces from various authorities, as localities for the species, not 
only many European stations, but also Madeira, Mauritius, Samoa 
and Panama, and states that it “lasst wahrscheinlich nur die 
arktischen Meere frei.” 
Pelagonemertes Rollestoni , Moseley. — This very remarkable, 
transparent pelagic nemertine was taken by the “Challenger” 
“ near the southern verge of the South Australian current,” lat. 50° 
V S., long. 123° 4' E., and was again recorded in the mouth of 
Yokohama Bay. It seems to be closely allied to the Pterosoma 
plana of Lesson, obtained in great abundance between the Mo- 
luccas and New Guinea during the voyage of the “ Coquille.” 
In the more recent monograph of the group by Biirger (F. and F. 
d. Gol.fes v. Neapel, Nemertinen, p. 596) attention is called to 
very marked differences, both external and internal, between the 
specimens of Pelagonemertes from the northern and southern 
localities, and that writer, without hesitation, erects the two forms 
into separate species, retaining the name P. Rollestoni, Moseley, for 
the Australian form, and giving the new name P. Moseleyi to that 
from Japan. Burger points out as diagnostic characters that in P. 
Moseleyi the body is about as long as broad, is constricted in front, 
behind, and in the middle, and that the gut possesses five pairs of 
diverticula ; whereas in P. Rollestoni the body is twice as long as 
broad, is constricted neither before nor behind, and the gut has 
thirteen pairs of diverticula. He points out further that the 
smaller form (from Yokohama) which had been assumed by 
