[119] NOTES ON ENTOZOA OF MARINE FISHES. 837 



Following are the dimensions of the two aleoholic specimens : 



Dimensions. 



Length 



Length of head 



Breadth of head 



Length of head and neck. . . 

 Breadtli of neck 



Length of contractile bulbs 



Length of first segment 



Breadth of first segment . . . 



Length of last segment 



Number of segments 



No. 



1. 



mm. 



2. 



30 



0. 



10 



0. 



36 



0.86 



0. 



16 







46 







04 







14 



1 



04 





5 



No. 



mm. 

 1.26 

 0.20 

 0.42 

 1.00 

 0.22 

 0.48 

 0.06 

 0.14 

 0.20 

 •3 



The first two segments are rather indistinct and indicated by two 

 transverse lines. The last segment in No. 1 is linear, rectangular, and 

 about the same breadth as the first segment. There is an ovary at the 

 posterior end and a series of comparatively large, subelliptical bodies, 

 presumably the testes filling up the interior. There is also a faint in- 

 dication of the beginning of a cirrus bulb just back of the posterior third 

 and near the margin. 



I would prefer to regard this species as a variety of R. hispidum if it 

 were not for the difference in the character of the hooks. 



31. Rhynchobothrium tenuispine, sp. nov. 

 [Plate xn, Figs. 1,2.] 



Head and neck much as in R. hispidum, but red spots in neck indis- 

 tinct or absent altogether. Proboscides long and slender, densely beset 

 with exceedingly minute spinose hooks, slightly swollen near the base. 

 A few of the hooks behind the tumid part are strongly recurved and a 

 little stouter than the others. On the tumid part and as far forward 

 as could be seen the hooks are slender, spinose, and slightly recurved. 

 On one side of the tumid base there are a few slender hooks with ab- 

 ruptly recurved points. First two segments usually moniliform ; re- 

 mainder of strobile much as in R. hispidum. 



Habitat. — Trygon centrum, spiral valve, August 1 and 3, 1887, Wood's 

 Holl, Massachusetts. 



In the following measurements from alcoholic specimens the diameter 

 of the head is the maximum, obtained by measuring the head in lateral 

 view, in which the bothria appear as widely flaring at the posterior 

 edges. Only the measurements of head, neck, and first segments are 

 given. In all the alcoholic specimens the posterior segments have 

 dropped off. 



