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INFUSORIA PARASITIC IN CEPHALOPODA. 183 
Some Observations on the Infusoria Parasitic 
in Cephalopoda. 
By 
Cc. Clifford Dobell, 
Fellow of Trinity College, Cambridge ; Balfour Student in the University. 
With Plate 1. 
INTRODUCTION. 
The infusorian parasites of cuttlefish are already well 
known from the excellent descriptions of their discoverer, 
Feettinger (5, 6), and the admirable figures of Gonder (7). 
From the work of the latter it would appear that the 
last word had been said about their morphology. But, 
as they are of particular interest on account of the 
peculiarities of their nuclear apparatus, I took the oppor- 
tunity afforded by a recent stay in Naples (March to June, 
1908) of re-examining these organisms. The results were 
somewhat unexpected, and are embodied in the following 
pages. 
OccURRENCE OF THE PARASITES. 
As is well known, three different Infusoria occur in 
cephalopods—O palinopsis sepiole, Chromidina (Bene. 
denia) elegans, and C. (B.) coronata.t The first— 
QO. sepiole—has been recorded from the liver of Sepiola 
rondeletii (Fcttinger, Gonder) and from the liver of 
Octopus tetracirrhus (Feettinger). - Although I have 
examined fifty-five individuals of Sepiola rondeletii, 
I have never once met with the parasite. But I have 
encountered it in a hitherto unrecorded host,—Sepia offi- 
cinalis,—and not only in the liver, but also in the kidneys. 
* Following Gonder’s nomenclature. O. octopi, Feett., is, as Gonder says, 
almost certainly identical with O. sepiole. Biitschli (2) united Opali- 
nopsis, Fett., and Benedenia, Fett. (= Chromidina, Gonder) into 
one genus—O palinopsis. 
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