NO. 1560. PARASITES OF BERMUDA FISHES— LINTON. 97 



Mycteroperca apua. 



July 22, several frag-ments from testes; intestine (lark-])rown with 

 elono-jited cells in its wails; ova, but no young, in the uterus; longest 

 fragment 75 mm. in length. 

 JVeonixnls, Kj^ccies. 



July 27, fragments from ovary; inte.stinc narrow, very dark; young 

 in uterus still active on the 28th. 



Order CESTODA. 



Cestodes were found in IS of the 5L species of hsh examined. 



There seemed to he a notable scarcity of encysted forms and espe- 

 cially of the small larvtB known as Scolex p)ol yiiiorpJnts^ which are very 

 conunon in the alimentary canals of our coast fishes. This may be 

 explained perhaps by the fact that most of the fish which were exam- 

 ined came from the inner reef. All the larger fish from the deeper 

 water on the outer reef, where sharks abound, had numerous cysts on 

 and in the viscera. Cestode flesh parasites were found only in the gar. 



DISCOCEPHALUM PILEATUM Linton. 



Plate V, %. 31. 



Discocephalum j^ileatum Linton, Report U. S. Fish Com. for 1887, pp. 781-787, 

 pi. X, figs. 1-7; Bull. U. S. Fish. Com. for 1899, p. 272. 



On July 31 seven of these cestodes were found with their heads 

 eml)edded in the mucous membrane at the anterior end of the spiral 

 valve of a small cub shark {Carcharhlnus platyodon). These worms 

 varied in length from 10 to 340 mm. Five of the largest were 

 attached within a space about 10 mm. square. Oidy two of the strob- 

 iles were immature. In the longer of the immature strobiles, which 

 measured 100 mm. in length, reproductive organs were developing in 

 the posterior segments. In addition to the attached strobiles there 

 were several fragments of mature strobiles in the ch3de. 



The disk-like heads, shaped like a mushroom anchor, were firmly 

 embedded in tiie submucosa with the mucous membrane closely embrac- 

 ing the necks. They can not be removed by simply pulling them 

 away from their lodgment. This would merely break them and leave 

 the heads securely embedded in the intestinal wall. Indeed, from the 

 appearance of the pits after the worms have been removed, it seems 

 doubtful whether they can detach themselves after they have once 

 gained lodgment. It is probable, however, that they can do so, since 

 the disk is a very muscular organ and doubtless is capable of assuming 

 very diverse shapes; besides there is no evidence of degeneration 

 either in the head or the surrounding tissue, which would be the case 

 if the heads were permanently attached. 



Proc. N. M. vol. xxxiii — 07 — -7 



