THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. V, No. 16.] MARCH, 1910. [^jrxvToT« 



A NEW SPECIES OF HOLOTRICH. 



BY NADINE NOWLIN. 



(Contribution from the Zoological Laboratory, No. 193.) 



Two text figures. 



IN April of 1909 there was brought to my room at the 

 Naples Station a jar of the small barnacle Lepas 

 pectinata, and in examining microscopically one of the 

 appendages I observed a minute rotifer-like animal creeping 

 along its edge. This animal, after being studied for some 

 time, was found to be an infusorian — a Holotrich, resembling 

 in a general way Huxley's Dysteria armata. Upon careful 

 study, however, it differed in so many ways that I concluded 

 it to be a distinct form. 



Symbiosis is such an old and well known condition in the 

 organic world that any discussion of it for its own sake is un- 

 necessary here. As in other cases, these two animals live 

 together, deriving mutual benefit from the combination; the 

 ciliate finding a shelter in the appendages and the barnacle, no 

 doubt, getting a tasty morsel when it succeeds in dislodging 

 the little animal long enough to sweep it into the gullet. It is a 

 question how the protozoon manages to thrive under these con- 

 ditions. We know that the water currents set up by the host 

 are swift and frequent, and life under such tempestuous condi- 

 tions would seem worse even than the chances in the open sea. 

 The structure of the smaller organism partially explains this. 

 It has first of all an armature, a tough siliceous skeleton, cover- 

 ing the body, except a narrow strip on the ventral side. With 

 this protection it is not easily crushed. Then caudally there 

 protrudes a hook-like tail, which not only helps the animal in 



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