AET. 21. PARASITES OP SHARKS AND SKATES LINTON. 25 



CALYPTROBOTHRIUM OCCIDENTALE Linton. 



1900, pp. 275, 298-299, figs. 94, 95, 97. 



1901, p. 432. 



1907a, pp. 155-157, fig. 2. 

 1907c, pp. 276-279, figs. 1, 2. 

 1911, p. 585. 



Records of this cestode not before published : 



Narcacion nobilianus. 



Collected in 5 of the years from 1908 to 1920 : On 3 dates in July : 



(1) 2, lengths 125 and 200 mm.; (2) 1 scolex and 2 fragments of 

 strobiles; (3) 1, in 1 of 4 torpedoes. On 2 dates in August: (1) 1; 



(2) few, at lower end of spiral valve, in 2 of 3 torpedoes. On 1 date 

 in October, 3 fragments of strobiles, 25, 75, and 120 mm. in length. 



(U.S.N.M., Helm. Coll. 7676.) 



LECANICEPHALUM PELTATUM Linton. 



1890, pp. 802-805, pi. 9, figs, 2-4. 



1900, p. 275. 



1901, p. 433. 

 1905, p. 347. 

 1910a, p. 695. 

 1911, p. 586. 



Following are records of finds of this cestode not hitherto pub- 

 lished : 



Dasyhatis centru<ra. 



Collected in 3 of the years from 1903 to 1922 : On 1 date in June, 

 2, and a few fragments. On 2 dates in July (1) 2, and a fragment; 

 (2) a few fragments. On 1 date in August, many, collected by Dr. 

 G. A. MacCallum. On 4 dates in September: (1) few; (2) 22; (3) 

 1; (4) 3, small, the only parasites found in the alimentary canal. 

 The ray had been kept in the pool for a few days, stomach empty. 



(U.S.N.M., Helm. Coll. 7677.) 



1923. On two dates in July and one in August : 2 to many ; in one 

 case the scoleces were adhering firmly to the mucous membrane of 

 the spiral valve; when placed in sea water the scoleces were very 

 active, the anterior portion forming a vase-like organ which is evi- 

 dently capable of acting as a sucker ; maximum length 25 mm. 



TRILOCULARIA GRACILIS Olsson. 



Plate 2, figs. 14-17. 

 1911, p. 589. 



Small cestodes found in the spiny dogfish are easily referable to 

 the genus Trilocularia^ and presumably belong to Olsson's species 

 T. gracilis. 



