[123] NOTES ON ENTOZOA OF MARINE FISHES. 841 



breadth of neck, 0.6 in,n ; length of neck, 4.5 mm $ length of last segment, 

 2.5 mm ; breadth, 1.65 mi ". A free segment, which I think belonged to 

 this specimen, measured 5 mm in length. When placed in sea-water it 

 discharged a mass of eggs which spread out on the bottom of the dish 

 making a spot 5 mm in diameter which was at first an opaque white 

 color changing after a few hours to dark brown. 



The following data were obtained from the alcoholic specimen : The 

 bothria are l mm in leugth and 0.7G mm in breadth. In lateral view, mar- 

 ginal as to the body, the head is 1.26 mm broad in posterior diameter, 

 0.6 mm in anterior diameter. The neck in front of the contractile bulbs 

 is cylindrical and about 0.6 mm in diameter immediately behind the both- 

 ria, increasing to 0.8 m,u immediately in front of bulbs. In the vicinity 

 of the bulbs the neck flattens to coincide with the flattened body. At 

 the base of the contractile bulbs the marginal diameter is 0.47 mm , lateral 

 O.G6 mm . Length of contractile bulbs*1.66 mm , breadth 0.28 mm . Approxi- 

 mate length of proboscides 2 mm ; diameter, exclusive of hooks, 0.1 mm , 

 diameter including hooks from 0.14 to 0.16 mm . In general there are 

 two sorts of hooks classified according to size. The largest hooks have 

 linear dimensions which are ten or even twenty times those of the 

 smallest hooks. There are, however, a few that are intermediate be- 

 tween the larger and smaller hooks. Of the larger hooks there are three 

 principal types. In the first type the hooks have broad bases abruptly 

 and strongly recurved, the recurved part parallel with the axis of the 

 proboscis or even turned a little toward the proboscis aud equal in length 

 to half the entire length. These hooks are the largest and strongest of 

 all. At the base of the proboscis they measure 0.06 mm from tip to oppo- 

 site extremity of basal support, length of base 0.04 mm , breadth of hook 

 near middle 0.02 mm . Toward the end of the proboscis these hooks grow 

 smaller, the corresponding dimensions of a similar hook there being 

 0.03 mm , 0.02 mm , 0.01 mm . There appears to be a single longitudinal row of 

 these stout hooks, with two additional rows of hooks of nearly similar 

 shape but smaller in size. The second type of large hooks is long, more 

 slender than the foregoing, and strongly but not so abruptly recurved, 

 with rather blunt points. One row stands near the row of stout hooks. 

 At the base of the proboscis they measure, with the curve, as much as 

 0.06 mm in length and are about 0.0L mm broad at base. Towards the 

 apex of the proboscis they become shorter and more slender. The tip 

 of the recurved part was in some cases observed to bend toward the 

 proboscis to form a% veritable hook. The third style of large hook is 

 slender, arcuate, rather sharp pointed, 0.04 mm in length and 0.013 nnu 

 broad at base, tapering uniformly to the tip. There are also some simi- 

 larly shaped hooks about one-half as long and about one-third as broad. 

 Closely allied to this style are some slender hooks which are curved in 

 two planes, like the horns of an ox. Next below these come the largest 

 of the small hooks, not more than 0.014 mm in length. The smallest hooks 

 are only about 0.002 mm in length. On one side of the proboscis these 



