[81] NOTES ON ENTOZOA OF MARINE FISHES. 799 



could not be determined. It is about .03 mm in diameter at base. The 

 interior of the segments was filled with long, oval masses, which lie close 

 together and at right angles to the long axis of the segment and along 

 the central part of the segment on each side of the median line. In the 

 anterior part of the segment the masses are globular, and along the 

 margins smaller and granular. 



The cirrus bulb lies in the crook of the vagina, and contains, besides 

 the retracted cirrus, a part at least of the vas deferens. When thin 

 sections of a stained segment were made, the cirrus was found to be 

 covered with exceedingly minute spines. The long-oval masses in the 

 interior of the segment now appear densely granular, or like nests of 

 nuclei in some of the segments ; in others which are more mature 

 they are not so much elongated, and contain both nuclei and fibrous 

 tissue. 



This species is apparently near Van Beneden r s Anthobothrium musteli 

 (Orygmatobothrium versatile Dies., Revis. Ceph. Par. p. 276). I have, 

 however, experienced the same difficulty in finding a second supple- 

 mental disk in the center of the bothria, as in the case of the specimens 

 which furnished the material for my former description. I notice the 

 same curved band of muscular fibres crossing the faces of the bothria 

 about the anterior third. This does not rise into a transverse rib. 



I am not at all satisfied that there is a second supplemental disk 

 (auxiliary acetabulum) in this species. It is certainly very faintly out- 

 lined by the curved band of muscular fibres.* 



Crossobothrium Linton. 

 18. Crossobothrium laciniatum Lt.f 



[Plate vn, Fig. 4.] 



U. S. Fish Commission Report for 1886, pp. 469-474 ; Plate m, Fig. 4-18. 



I have already given a tolerably full account of this parasite of the 

 sand shark (Odontaspis littoralis). 



* In attempting to follow Diesing's system of classification of the unarmed Tetra- 

 bothriidcel have experience rl much perplexity, and nowhere more than among the 

 forms kindred to those which Van Beneden has grouped under the generic name 

 Anthobothrium. 



The specimens which I have referred to the genus Orygmatobothrium possess many 

 of the characters ascribed to the genus Monorygma Dies. There is, however, no 

 myzorhynchus, unless an indistinct papilliform apical termination of the head be 

 regarded as such. 



Diesing'.s genera Orygmatobothrium and Monorygma are included by Van Beneden 

 in his genus Anthobothrium. 



t This species bears a close resemblance to Oerley's Orygmatobothrium Dohrni : Die 

 Entozoen der Haien und Eochen, p. 219, pi. x, figs. 16-19, Phyllobothrium Dohrni Oerley, — 

 Zschokke, Mem. Inst. nat. Genev., vol. xyn, 328-338, pi. vm, fig. 138 and pi. ix, figs, 

 139-144. 



