808 LARVAL CESTODE PARASITES OF FISHES— LINTOX. 



Dimensions of alcoholic specimen. — Length of cyst, 0.47; diameter of 

 cyst, 0.27; length of bhistocyst, 0.3; diameter of bhistocyst, 0.12; lengtli 

 of contractile Imlbs, 0.080 ; diameter, 0.043; diameter of proboscis, about 

 0,02; hooks very small, about 0.0] in length. 



Proboscides slender, lioolcs strongly recurved. Possibly young stage 

 of Tetrarhynchus robustum, Linton. 



2. iMinute cysts from intestinal walls of hammerheaded shark ( Sphijrna 

 zijijuena) (Xo. r)470, U.S.X.M.), Woods Iloll, Massachusetts, July 28, 

 188G. Length of blastocyst, 0.5C mm.; diameter at larger end, 0.45, 

 tapering to a blunt point at the smaller end. Embryo a small granular 

 mass, near larger end 0.0!) mm. in dianu'ter. 



3. Small cysts from the cero {Scomberomorns regalis) (No. 5494, 

 U.S.X.M.), collected at Woods Holl, Massachusetts, August 12, 1886; 

 July 30, 1887; August and August 13, 1889. 



Dimensions of (dcoholic specimen slightly compressed. — Length of cyst, 

 1 mm. ; breadth of cyst, 0.75 ; length of larva, 0.33 ; length of bothrium, 

 0.13; breadth of head, 0.17; length of contractile bulbs, 0.09; breadth, 

 0.00(5; hooks very minute, about 0.005 in length. 



Possibly young stage of Tetrarhynchus teuiie, Linton (No. 4819, 

 U.S.N.M.). 



4. Tetrarhynchus cha'todijfteri, from abdominal cavity of Chniodipte- 

 rus faber,^ or Ih Carolina coast, October, 188(5, collected for the United 

 States Fish Commission by S. E. Meek, Fulton Market, New York. 

 The cysts were in small clusters in the abdominal cavity of the host. 

 One cluster was 12 mm. long and 7 broad — all the cysts small; a 

 typical one measured 1.7 mm in length and 0.88 in breadth. 



Dimensions of cyst and embryo. — Length of cyst, 1.3 mm.; breadth, 

 0.7; length of embryo, 1.14; length of bothria, 0.38; length of con- 

 tractile bulbs, 0.31 diameter of bulbs, 0.15; diameter of proboscis, 

 exclusive of hooks, 0.017; length of longest hooks, 0.011. The inner 

 face of the proboscis bears extremely small bristle-like hooks. The 

 outer face bears, for the most part, rather stout, recurved hooks 

 (Plate Yl, fig. 9.). 



5. Cysts from stomach wall of the sting ray (Trygon ccntrura) (Nos. 

 5477, 5478, 54S1, U.S.X.M.), collected at Woods Iloll, IMassachusetts, 

 August 14, 1885, July 27, 188G, July 18, August 3 and 10, 1887, and 

 July 24, 1889. 



The cj'sts are small and contain small subconical blastocysts, which 

 have a rudimentary embryo near the larger end. 



Dimensions of alcoholic specimens. — Length of blastocyst, 1.44 mm.; 

 diameter at larger end,*0.94; diameter at smaller end, O.IG; length of 

 embryo, 0.144; diameter of embryo, (►,08, Calcareous bodies are present 

 in the blastocysts, and some cysts were found in which the contents 

 had degenerated. Two cysts, belonging one to each of the first two 

 lots, are larger than dimensions given above — 3.5 mm. in length. For 

 the others the dimensions given are typical. 



