UNIVERSITY OF CALIFORNIA PUBLICATIONS 
ZOOLOGY 
WOls Ay IN@s Zp joe Grorteils Veale le December 21, 1904. 
CONTRIBUTIONS FROM THE LABORATORY 
OF THE 
MARINE BIOLOGICAL ASSOCIATION OF SAN DIEGO. 
Tn 
THE CTENOPHORES OF THE SAN DIEGO 
REGION. 
BY 
HARRY BEAL TORREY. 
Ord. CYDIPPIDA. 
Ctenophorae spherical, cylindrical or compressed, with or without 
winglike aboral processes; two simple or pinnate tentacles usually retractile 
into a sheath; meridional and oesophageal canals end blindly. 
Fam PLEUROBRACHIIDAE. 
Cydippida without winglike aboral appendages. Body approxi- 
mately round in cross section. Sub-tentacular and sub-oesophageal rows of 
swimming plates equal in length. 
Gen. Euplokamis, Chun, 1880. 
Body elongated; cylindrical or moderately compressed; rows of 
swimming plates reaching from pole to pole; tentacle sheath present. 
Three ctenophores taken in Prince Wilham Sound, Alaska, by 
Professor Ritter, and now in the collection of the University of 
California, belong undoubtedly to Mertens’ Beroe cucumis 
(EKuplokanis cucumis, Chun). All are compressed somewhat, so 
that the transverse diameters are to each other as 6 to 5. Plewro- 
brachia, a typical example of a spherical ctenophore, may also 
be compressed to the same extent. For these reasons, too much 
stress should not be laid on the cireular cross section of Euplo- 
kamis, which is rather to be distinguished from Pleurobrachia by 
its elongation, from Mertensia by its sight degree of compression 
and equal rows of swimming plates. According to recent figures 
by Vanhoffen (:04), cross sections of specimens of Mertensia 
ovum taken in Greenland were three to four times as long as 
broad. 
