Some Points on the General Anatomy of Gyrocotyle. 721 



Watson worked. Unfortunately these went astray in the mail and 

 it has been impossible up to the present time to make good the loss. 

 Some points can not be adequately discussed in advance of a 

 comparison of this material with my own specimens. Meantime it 

 has seemed wise to utilize part of the work in the present paper 

 which deals chiefly with the general anatomy. 



General Anatomy. 



In life the body of Gyrocotyle when moderately contracted is 

 of a nearly opaque creamy white appearance that is bnt little altered 

 by proper preservation. I clid not have an opportunity to study 

 specimens in extension; they are said to be more transparent. In 

 alcoholic specimens the worin appears chalky white on the one hand 

 or somewhat yellovvish on the other according to the preservative 

 employed and the length of stay in alcohol. My own specimens were 

 very uniform in size, the worms in alcohol measuring 20 to 23 mm 

 in length by 8 to 15 mm in breadth. The specimens from Paeker 

 varied a little more widely but were about the same size and stage 

 of sexual development. Apparently Watson does not indicate the 

 size or ränge in size of the specimens she studied. Wagener had 

 specimens which measured when extended 50 mm in length and 

 15 mm in width while the smallest he found was only 8 mm long 

 and 1,5 mm broad in extension. The latter was so young that the 

 sexual organs were only at the start of their development. Lönnberg 

 also has recorded the discovery of young forms but the developmental 

 stages are as yet entirely unknown. 



In life the worm is flattened, leaf-like or linguiform when 

 extended; preserved specimens, unless confined between glass plates 

 when killed, are more or less contracted (Figs. 1 and 3). The body 

 is thick, compressed, and conspicuously wrinkled. The folds or rolls 

 of skin are irregulär, variable in number, size, precise location, and 

 in extent, yet in a superficial way they distinctly suggest metameric 

 segmentation. They are as in many other cases only surface wrinkles 

 and I have been able to trace no relation between them and internal 

 Organization. The general appearance of such a preserved specimen 

 recalls strikingly the surface structure of the cestode proglottid 

 under similar conditions of marked contraction. The transverse 

 folds or wrinkles, which are only the expression of the action of the 

 body musculature, are more prominent and the reduction in length 

 of the worm greater than ordinarily is found, in the Ankes, even 



Zool. Jahrb.,' Suppl. XV (Festschrift für .T. W. Spengel Bd. II). 4fi 



