[109] NOTES ON ENTOZOA OP MARINE FISHES. 827 



species. There seems to be a considerable degree of diversity in the 

 hooks on different sides and in different parts of the same proboscis. 

 In general there appear to be three different styles of hooks. One kind 

 is very minute, while of the larger and more conspicuous hooks one 

 sort is broad and abruptly recurved, the other long and slender. The 

 broad hooks are about .008 lum long and .006 mm wide at the base, maxi- 

 mum. They resemble pruning-hooks with short, stout blade. The long, 

 slender hooks are of two kinds, one with an abruptly recurved apex, the 

 other uniformly arcuate, tapering gradually to an acute point. The 

 length of the long, slender hooks is about .016 mm , breadth at base 

 .0027 mm . The arrangement of the small hooks at one point is shown in 

 Fig. 1, Plate xi. 



The distribution of the hooks appears* to me to be somewhat in this 

 wise : There is first a longitudinal series of short, broad hooks, appar- 

 ently in two double rows, flanked on either side by a series of long, 

 slender hooks with recurved points and arranged side by side in groups 

 of three ; the two latter series are separated from each other on the side 

 of the proboscis opposite the short, broad hooks by a series of slender, 

 arcuate hooks with other minute booklets interspersed. Of the latter 

 there are two longitudinal rows on either side of arow of the largearcuate 

 hooks. Each hook in the latter row has a small hooklet situated near 

 its base on the posterior side. 



Anatomy of mature segments. The following data were obtained from 

 stained sections and from segments stained with carmine, hnematoxylon, 

 green, and red aniline respectively, and studied entire. The best results 

 were obtained from an almost mature proglottis which had been flattened 

 between two cover glasses, killed while in that position, stained with 

 Beale's carmine, made transparent in oil of cloves, and studied entire. 

 This segment was long, oval, somewhat slipper-shaped, length 6 mm , 

 breadth 2 mm . The reproductive opening was marginal a little in front 

 of the posterior third. The greater part of the interior was filled with 

 roundish, granular bodies from .08 .to .12 mm in diameter. These, when 

 highly magnified, are seen to consist of a thick coat of dense fibrous 

 tissue, inclosing a nest of nuclei or small granules. Behind the ovaries 

 these granular bodies are more elongated and more closely crowded. 

 These granular bodies, at least those which occupy the central parts of 

 the proglottis, I take to be the spermatic capsules of the testes. 



The ovary is situated near the posterior end of the proglottis and 

 consists of two finely granular lobes, which are separated along the 

 median line for the greater part of their length, but are confluent be- 

 hind. Threy are surrounded on all sides in the same plane by the gran- 

 ular bodies mentioned above. 



There are three distinct tubular organs in the interior of this pro- 

 glottis, to which I give the following interpretation : First, the vagina, 

 a comparatively large duct which appears to have its exterior opening 

 at the margin, coincident with or immediately behind the opening of 



