NOTES ON A PECULIAR ACTINOZOAN LARVA. 



L. R. GARY. 



For a number of years past a few specimens of a large trocho- 

 phore-like larva have been taken each summer in the tow near 

 Beaufort, N. C., but they have never been seen to transform. 



While at the laboratory of the United States Fish Commission 

 at Beaufort, 1 during the past summer, I had the good fortune to 

 secure a number of these peculiar larvae. 



The larvae were taken while towing outside the harbor on 

 August 15, after a heavy southeast storm which had continued 

 for two days, and which had driven in shore specimens of several 

 forms not usually found inside the Gulf Stream. 



These larvae were taken to the laboratory and at the sugges- 

 tion of Dr. Caswell Grave, of the Johns Hopkins University, were 

 put in aquarium jars of sea-water containing sand rich in diatoms. 

 By this method they were kept alive for the remaining seven 

 weeks of my stay at the laboratory. 



The larvae, Figs, i and 2, are elongate-oval in shape when in 

 an active state, changing to a very nearly spherical form when they 

 are disturbed. They are from two to four millimeters in length, 

 and of a light brown or cream color. 



At a point about one fourth of the distance from its anterior 

 end, the body is encircled by a ridge which lies at the bottom of a 

 shallow groove. This ridge bears on its surface two parallel 

 bands of long stiff setae, Fig. 4. The setae -bearing ridge is not 

 continuous around the body, but on one side it is interrupted and 

 the ends overlap for a short distance, Fig. I. 



The whole surface of the body is provided with a covering of 

 short cilia which are the true locomotor organs. The function 

 of the bands of setae is not apparent. They move only at irreg- 

 ular intervals, and then the force of their movement is in a direc- 

 tion antagonistic to the progress of the larva. 



1 1 am indebted to the Hon. G. M. Bowers, U. S. Commissioner of Fisheries, for 

 the privilege of occupying a table at the Beaufort Laboratory, and to Dr. Grave, the 

 director, for many favors received while there. 



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