u 



408 BULLETIN OF THE BUREAU OF FISHERIES. 



These larvse are found on the viscera generally, but especially on or near, occasionally in, the liver, 

 and in the mesentery. Early in the seas f 1901 I was struck by the large numbers of blastocysts 



clustered together in comparatively small compass. [Fig. 59.] The frequent recurrence of these 

 clusters led me to examine them with some care with the hope that the reproduction of successive 

 generations of blastocysts by some process of budding could be demonstrated. The cysts are, as a rule, 

 comparatively thin-walled. The blastocysts are club shape, the part representing the handle of the 

 club being usually much, often enormously, elongated. [Fig. 62.] 



Dimensions of one, in millimeters, life: Enlarged anterior portion M in length and 1 in diameter; 

 slender posterior portion 9 in length and 0.1 in diameter. This specimen enlarged slightly into a 

 rounded knob at the extreme posterior end, a characteristic feature of these blastocysts and possibly 

 having some bearing on the method of development of new blastocysts. 



The larva is situated in the enlarged anterior portion. When a blastocyst is subjected to slight 

 pressure the larva may be seen through the transparent walls at the anterior end of the enlarged 

 portion. The parenchyma of the blastocyst contains numerous calcareous bodies, which often are 

 rather irregularly shaped. Upon continued pressure, especially if aided with needle points or similar 

 tool, the larva may be liberated from the blastocyst [fig. 64]. When so liberated it separates from the 

 blastocyst. Even when separated entirely from its blastocyst its bothria often remain retracted. 

 They may be seen in some instances protruding from the anterior end of the scolex. What is thus 

 seen is of course the posterior edges of the bothria, since in retracting the head it is really inverted 

 and the last part of the bothria to disappear is the posterior bonier. Usually the bothria may be made 

 to appeal- by suitable manipulation, although I did not succeed in getting them' to expand freely after 

 they had been thus unsheathed. The bothria are leaf-like and have the characteristic loculi of the 

 genus Rhinebothrium. The number of loculi on each bothrium was found in one favorable example to 

 be as represented in fig. 71; that is, 27 on each side with an odd one at each end, or 56 in all. One 

 character possessed by these larva-, which would at first glance ally them with Vkheneibothrium rather 

 than Rhinebothrium, is a terminal aperture into which the bothria may be retracted. This is a 

 character, however, which is possessed by cestodes generally during larval stages of the scolex. 

 Doubtless the larva' of the genera Rhinebothrium and Echeneibothrium will be found to be much alike. 

 (See above under Scolex potymorphus.) 



It is not unusual to find two or more blastocysts each with a larva inclosed in the same cyst. 

 Attempts to demonstrate the vital connection between two blastocysts each containing a larva by 

 means of sections have not been successful. A cyst containing two blastocysts each containing a well- 

 developed scolex was sectioned and the sections mounted serially. The long tail-like portions appeared 

 upon the iirst study of the sections to be continuous with each other, which would have amounted to 

 a demonstration of budding. A careful reconstruction of the sections, however, showed that the two 

 blastocysts were independent of each other. 



An interesting case in this connection, although demonstrating nothing, is shown in tig. 66, 

 sketched from a cyst which was stained and mounted in balsam. The cyst, is small, 1.41 mm. in 

 length, shaped like a dumb-bell, completely invested with a connective tissue cyst, but with undoubted 

 continuity of the material of the blastocyst. Further dimensions of blastocyst, in millimeters: Length, 

 of larger end 0.45, of smaller end 0.21, of connecting part 0.65; diameter, of larger end 0.30, of smaller 

 end 0.19, of connecting part 0.09, in the middle, constricted to 0.027 anil 0.021 near the larger and 

 smaller ends, respectively. 



1901. — July 9, numerous cysts on liver, stomach, intestine and mesentery. July Hi and 18, 

 numerous on viscera. In one of the fish the long tails of the blastocysts were felted together in a 

 mass on the mesentery. July 26, very numerous, in a cluster 21) mm. square and containing several 

 hundred cysts on the mesentery. One cyst in this lot contained three blastocysts, each with a larva. 

 Aug. 2, numerous on liver, stomach, and intestine, some in clusters. Aug. :); numerous in cluster in 

 one of the fish, few on the liver in the other. Aug. 6 and 8, numerous, clustered. Aug. 9, numerous 

 in clustered cysts on serous coal of rectum. Aug. 12, 1.'!, It>, 20. 21, 22, 2:;, numerous clusters of cysts 

 on viscera on each date. Aug. 27, clusters of cysts on rectum, in and on liver, cysts in stomach wall. 

 Aug. 29, numerous clusters of cysts on liver and other viscera. Aug. 30, few, cysts on viscera. 



Clusters of cysts containing blastocysts ami larva' on viscera. 



1902. — July 14, 19, numerous. July 21, 22, several, also elongated cysts with blastocysts, but no 

 larva' [lig. 84]. July 26, 28, numerous. July 29, 2.u, 31, several. Aug. 4, numerous. Aug. 7, S, not 



