The Morphology of Coeloplana. 43 
otolith sac with its enclosed otolith. On either side surrounding it, 
were two curious half moon shaped diverticula of the gastric cavity.!) 
In the opposite plane were the characteristic Cydippid tentacles 
each enclosed in a flask-shaped sheath. 
Notwithstanding its Planarian-like appearance KoWALEVSKY 
concluded that so far as his rather superficial examination went, 
Coeloplana was more Ctenophore than Flatworm. He considered the 
plane of the tentacles as right and left, that is, sagittal. 
2. Korotnerr’s Ctenoplana. 
Some four years later, another Russian scientist, ALExIs 
KoROTNEFF, caught in the tow-net, on the west coast of Sumatra, a 
single specimen of an animal that was very evidently closely related 
to Coeloplana but presenting marked points of difference. This form 
was much more like a typical Ctenophore than Coeloplana and to it 
KOROTNEFF gave the name Ütenoplana. In addition to the characteristic 
otolith and tentacles which had been described for Coeloplana, 
KOROTNEFF also described eight rows of Ctenophoral costae, the 
individual. combs of which, however, were reduced to seven in 
number. Each costal row was retractile into a cup-shaped cavity 
of the body wall. The rows of costae were separated in one plane 
by the tentacle sheathes and between the other rows the body was 
thrown up into folds, — the whole effect being to give a stellate 
appearance tothe dorsal surface. In Korornerr’s figure there is a 
notch in the periphery on either side, in the plane at right angles 
to the tentacular plane. 
About the otolith was a circlet of sensory tentacles (11 in his 
figure) and the whole body surface is described at ciliated. KoROTNEFF 
described and figured the structure of the otolith and its cup in 
some detail. According to him the mouth leads directly into a 
central cavity from which the gastric canals arise, and above which 
there is a structure like the Ctenophor infundibulum, consisting of 
1) The abstract in the Zoologischer Anzeiger reports these: “Vor 
und hinter diesem Bläschen (i. e. the otolith) gewahrt man die erweiterten 
scheinbar blinden Enden zweier Canäle, die vom Magen ausgehend gegen 
die dorsale Körperfläche gerichtet sind”. The obvious but misleading 
interpretation of this statement seems to have lead LANG astray in one of 
his homologies. Vide post. 
