[97] 



NOTES ON ENTOZOA OF MARINE FISHES. 



815 



ends are turned outward and forward over the hooks, as is often the 

 case in active worms, a short neck is revealed, which is cylindrical and 

 lightly tumid just back of the point of attachment of the bothria. The 

 neck or anterior part of the body is very elastic and in life contracts 

 and expands constantly. Transverse striae appear very soon and seg- 

 ments .make their appearance soon after the striae begin. A few of the 

 first segments are broader than long. These are followed by a few 

 which are as long as broad. The subsequent segments are longer than 

 broad. The posterior segments are usually several times as long as 

 broad; occasionally they are contracted until they are nearly as broad 

 as long, often with narrow extremities. 



Genital apertures marginal, about posterior third. Cirrus long and, 

 so far as observed, smooth ; vas deferens long and much convoluted. 

 Vagina a slender tube opening in front of cirrus. Ovaries two oblong 

 lobes lying on either side of the median line, confluent at posterior end 

 of segment and occupying nearly the posterior third of the length of 

 the segment. The ova are relatively large. They were frequently seen 

 issuing from the ruptured walls of mature segments which had lain for 

 a few hours in sea water. They are globular in shape and consist of a 

 granular center surrounded by a thick but perfectly transparent 

 envelope, with a very thin limiting membrane. In some the granular 

 interior appeared to be undergoing segmentation. This segmented 

 interior in some of the ova had assumed a stellate shape on account of 

 prolongations of its substance, which penetrated the surrounding 

 envelope. These prolongations were generally knobbed at the ends. 

 Measurements of several ova which had escaped from a mature segment 

 and had been lying for some time in water gave the following results: 





Longer 

 diameter. 



Shorter 

 diameter. 



1 



2 



Mm. 

 0.32 

 0.24 

 0.26 

 0.26 

 0.18 



Mm. 

 0.26 

 0.20 

 0.22 

 0.26 

 0.16 



3 



4 



5 





The ova evidently increase in size after being discharged from the 

 segment, by the imbibition of water through the investing pellicle. 



VanBeneden describes and figures the ova of G. eschrichtii as having 

 very long filamentous appendages. While I have never seen any 

 appearance of that kind in the ova of my specimens there does not 

 seem to be anything inconsistent with it. The thick transparent en- 

 velope which surrounds the granular or nuclear interior might assume 

 under certain conditions of contraction very diverse shapes. 



It will be seen by the foregoing description that there are some iin- 



