[33] NOTES ON ENTOZOA OF MARINE FISHES. 751 



that it was found impossible to dislodge them without injuring the filamentary head 

 and neck. As if to make the anchorage doubly secure, the cartilaginoid thickening 

 of the invaded pancreatic cajcum had degenerated into a calcareous and contract' <l 

 cylinder, twisted upon itself in various ways. 



The specimens were in alcohol when they were submitted to me; I 

 am therefore unable to give measurements ot living specimens. 



The largest of the specimens measures C55 mm in length. The ante- 

 rior part for a distance of 20 111IU was buried in one of the pyloric caeca 

 and was removed with difficulty, by cutting away the enveloping coiouin. 

 The latter had degenerated into a brown, waxy secretion, which was en- 

 veloped by the serous coat, and formed a much twisted, rigid tube sur- 

 rounding the anterior part of the worm. When this encasing tube was 

 removed, it was found that all appearance of bothria or anterior seg- 

 ments had disappeared. That part of the worm which had been in- 

 closed in the tube was reduced to a slender white filament about .5 mm 

 in diameter. In another specimen the inclosed anterior part was irreg- 

 ular in outline and graduated into a yellowish, corneous substance at 

 the tapering apex. In this case the anterior end of the parasite had 

 undergone a degeneration of its tissues similar to that of the creca of 

 its host. 



The body is not distinctly segmented at first, but is crossed by in- 

 numerable fine wrinkles. The breadth near the anterior end is 2.5 nim . 

 It narrows abruptly at the point of entrance to the ca3cum. Near the 

 middle of the body the breadth is 3.5 mm , the length of the segments 

 .85 mm , increasing to l mm . The posterior part of the body, for a distance 

 of about 40 mm , is much wider, with crowded segments. Breadth, G uim ; 

 length of segments, .45 mm . This is evidently due to unequal contraction. 

 Thickness of the body about l mm in front, and approximating 2" im in 

 median and posterior segments. Another specimen had the following 

 dimensions: Length, 560 mm ; anterior part, inclosed in crecal tube, G miu 

 in length, .4 mm in diameter; breadth near anterior end, 2.5 mm ; middle, 

 5mm. length of median segments, .7 mm ; breadth at beginning of posterior 

 fourth, 4 mm ; length of segments, l mm ; breadth at posterior, 6 mm ; length 

 of posterior segments, .45 mm ; body rather plump, posterior half about 

 2 mm thick. 



One of the lateral sides of the strobile has a row of apertures making 

 an irregular zigzag series along the median line. These apertures are 

 oblong, the long axis coinciding with the long axis of the body. These 

 lateral apertures were at first naturally taken to be the genital aper- 

 tures. A careful examination with an ordinary lens revealed what ap- 

 peared to be marginal apertures. These were indistinct, but I was led 

 to make transverse and longitudinal sections of a series of segments in 

 order to demonstrate the position of the genital apertures. 



The first sections were made from, segments taken from the posterior 

 end of the body. The marginal position of genital apertures was at 

 once proved. In all cases where they were observed the external open- 

 ings were obscured by the close approximation of the sides, so as to form 



