ART. 21. PARASITES OF SHARKS AND SKATES LINTON". 91 



The face of the strobile on whicli ova lie is convex, the opposite side 

 is concave; ova somewhat variable, but the larger ones measured 

 about 0.031 by 0.024 ; shells of ova very thin. After the larger speci- 

 men was straightened by wrapping it around the handle of a needle- 

 holder and immersing it in the killing fluid, it measured 212 mm. 



Galeocerdo arcticus. 



1905, August 26: 3 scoleces, adhering to mucous membrane of 

 stomach; ivory white. 



1913, August 13: 1, attached to mucous membrane of stomach; 

 length of scolex 5 mm., of strobile, 6 mm., segments beginning, short 

 and much narrower than the scolex; collected by Dr. G. A. Mac- 

 Callum. 



1914, August 12: 6 scoleces from the mucous membrane of the 

 stomach ; at one point where some of these were attached there was 

 considerable suppuration; color white, yellowish behind the bulbs. 

 All short, but on© showed the beginnings of a strobile. This one 

 measured 18 mm. in length ; no segments. 



1915, August 6 : Associated with T. Msulcatus, a number of them 

 being attached together near the anterior end of the stomach in a pit 

 of the mucous membrane which was abraded and inflamed. 



(U.S.N.M., Helm. CoU. 7721.) 



Larval stage. 



Echeneis naucrates. 



1920, August 31 : 5, white globular cysts, 3 mm. in diameter, from 

 serous coat of stomach and intestine ; ivory white. 



Lophius piscafoHus. 



1910, July 29: 1, length 7 mm., white; from viscera. 



JSarda sarda. 



1910, June 27 : 2, under peritoneum ; one white, the other yellow. 



Xiphias gladius. 



1904, July 15 : Many, on viscera, in each of four swordfish; mostly 

 yellowish white, some ivory white; active; 6 to 12 mm. 



1911, July 13 : 10, in globular cysts on viscera. 



1912, July 20 : 1, from viscera, yellowish. 



TETRAKHYNCHUS BISULCATUS (Linton). 



.Adult stage. 



1899, Rhynchobothrium bisnlcatum, pp. 479-484, pi. 4, figs. 9-23. 



1890, Tetrarhynchvs bisulcatw^, pp. 857-862, pi. 14, figs. 10-12 ; pi. 15, fig. 1. 

 18970, p. 452. 



1900, p. 272. 



1901, p. 427. 



1905, pp. 340, 341, .344. 

 1910b, p. 1201. 

 1911, p. 589. 



