l [117] NOTES ON ENTOZOA OF MARINE FISHES. 835 



One free segment, alcoholic, measured 2.G mm in length, 0.22 mm in 

 breadth at anterior end, 0.1G mm at posterior end, and0.32 mm at posterior 

 third at the genital aperture. 



Many of the alcoholic specimens have the proboscides everted as much 

 as .7 lum , or more than three times the length of the bothria. Their diam- 

 eter is about ,02 mm , exclusive of hooks ; greatest diameter observed 

 from tip to tip of hooks, .04""". 



The character and arrangement of the hooks is shown in the sketches. 

 There is a single longitudinal row of short hooks with very broad bases. 

 1 On each side of this row there is a series of about four rows of long 

 slender hooks, and on the opposite side of the proboscis a series of about 

 five small slender hooks. There is considerable variety in shape and 

 size of the slender hooks. The broad hooks are recurved at the point 

 and widen rapidly towards the base, at which there is a prominent 

 posterior prolongation, which makes the length of the base exceed the 

 length from base to apex. One of the broad hooks measured ,011 mm 

 in length, while the breadth of the base was .01G mm ; another .OOS mm in 

 length was .Oll mm broad at base. The hooks are larger at the base of 

 the proboscis than they are at the apex. The slender hooks present 

 rather more variety in size, if not also in shape, than the broad hooks. 

 In general they are somewhat longer than the broad hooks, slender, 

 tapering uniformly to the point and slightly recurved or arcuate. They 

 also become smaller towards the apex of the proboscis. One of the 

 largest measured .013 mm in length and .004 mm in breadth at base. 



The ova, which were seen issuing from the posterior segment of a liv- 

 ing specimen under the compressor, measured .025 nuu in diameter. 

 They consist of a thin, fragile hyaline shell surrounding a clear space 

 in which is a granular nucleus. 



The last segment in the largest specimen contained mature ova. The 

 last but one is characterized by having the greater part of the interior 

 filled with rather large, oblong, or squarish masses, which lie in two 

 longitudinal rows on either side of the median line. The median and 

 anterior parts of the segment are filled with ova. 



The male genital aperture is marginal and near the posterior third. 

 The segment usually has its greatest diameter in the vicinity of the 

 genital aperture. In one segment a smooth, slender cirrus was extruded 

 from the center of a wide marginal sinus. I have not yet succeeded in 

 demonstrating the position of the vaginal aperture. The posterior seg- 

 ments in alcoholic specimens are often arcuate. 



30. Rhynchobothrium longispine, sp. nov. 

 [Plate xi, Figs. 18-20.] 



Head short and broad. Bothria two, marginal (? ), suborbicular, 

 widely separated ; neck rather long, broader than first segments ; pro- 

 boscides long, slender, and armed with relatively large, prominent hooks; 



