[13] NOTES ON ENTOZOA OF MARINE FISHES. 731 



cirrus-bulb and communicates with the ovary. The latter organ is 

 centrally placed and lies next the inner side of the lateral muscular 

 . wall on the side opposite the genital aperture. 



I The testes are represented by granular masses in the marginal parts 

 . of the inner core. 



The following measurements will assist to an understanding of the 

 proportions and arrangements of the various muscular layers of the 

 body: thickness of inner core at center .10"""; near margin .08 mm ; 

 thickness of longitudinal muscle layer .2 lnln ; thickness of inner granu- 

 lar layer .12 mm ; thickness of outer granular layer .16 mm . The layers 

 of circular fibers are very thin, averaging about .Ol imu in thickness. 



Breadth of inner core, margin to margin, 3.G nnn ; breadth of segment 



4.111111 



Longitudinal sections were carried through several contiguous seg- 

 ments. In these there were no septa to indicate a division of the body 

 into true segments. The only indication of a segmented condition 

 is the superficial character of projecting posterior edges. The longi- 

 tudinal muscles are continuous and the ovaries are crowded together 

 so as to form an almost unbroken zig-zag line. So far as any internal 

 characters go, the body is practically continuous. 



The above observations were made on sections lightly stained with 

 ammonia carmine. The sections used in the description are from one 

 of the specimens from Tetrapterus albidns. 



Habitat. Tetrapterus albidus, intestine, young and adult, July, 1885 ; 

 Histiophorus yladius, intestine, adult; August, 188G. Off Newport, 

 Rhode Island. 



3. Dibothrium punctatum Eudolphi. 

 [Plate n, Figs. 1-4.] 



Boilirioceplialus pnnctatns Rndolphi, Entozoa Hist., m, 50, and Synopsis, 138 

 and 475. Lenckart, Zool. Bruchst., 40 and 04, PI. I, 40. Dmmmond, 

 Charleswortk's Mag. of Nat. Hist., n, 574. Eschricht, Isis 1839, 344, and 

 in Nov. Act. Nat. Cur. i, xx, Snppl. u, 77 and 59, PI. in, 17-18. Dujar- 

 din, Hist. Nat. des Helm., 617. Bellingbam, Ann. Nat. Hist., xiv, 254. 

 Van Beuedeu, Bull. Acad. Belgique, xvi, n, 278, and in Meui. Acad. 

 Belgique, XXV, 1C1, PI. xxi. Spencer Cobbold, Trans. Linn. Soc., xxn, 

 157. Olsson, Lnuds Univ. Arsskrift, IV, 11. Von Linstow, Compeud. 

 Helm., 237. 



Dibothrium punctatum Rndolphi, Diesing, Syst. Helm., i, 593; Sitzuugsb., 

 xin, 579; Revis. der Ceph. Ab. Par., 240. Leidy, Proceed. Acad. Phila., 

 vn, 444, and vni, 46. Molin, Denkscb. d. kais. Akad, xix, 235. 



For additional bibliography, etc., see Diesing's Syst. Helm, and Revisions. 



Diesing's description of tbis species is as follows : Head oblong, rather broad, 

 with oblong lateral bothria. Neck none. First segments elongated, sub- 

 sequent segments snbquadrate. Genital apertures opposite on tbe lat- 

 eral face of each segment. Length, 300 to 450 min . 



This species has been very fully described by Mueller, Rudolphi, 

 and others. It is said to be an abundant species in various fishes of 



