ART. 21. PARASITES OF SHARKS AND SKATES LINTON. 29 



On 2 dates in June : 2 skates ; 1 on one date ; on the other date 4 

 with scoleces, and about 6 with scoleces missing; maximum length 

 60 mm. 



On 1 date in July: 3 skates; 19 strobiles slender and filiform; 

 scoleces adhered firmly to bottom of dish; maximum length 54 mm. 



On 1 date in August: 1 skate; 1, length 60 mm. 



On 1 date in September : 1 skate ; 3, length 16 mm. 



On 5 dates in October : 5 skates ; 1 to 8, 19 in all ; maximum length 

 66 mm. 



On 1 date in November: 1 skate; 6 and a few fragments. 



(U.S.M.N., Helm. Coll. 7682.) 



The scolex is often firmly attached to the mucous membrane of the 

 spiral valve, and, unless care is taken, may not be secured in collect- 

 ing the strobiles. 



Raja eglanteria. — While examining preserved material from this 

 host, which had been identified at the time of collecting as A. paulum,, 

 a few individuals were found which differed from that species in the 

 character of the hooks in a marked degree (see figs. 32 and 33). The 

 scoleces were much contracted, and difficult to interpret; one, how- 

 ever, was seen in which three accessory suckers could be made out in 

 that part of the bothrium which is anterior to the hooks. Length 

 of bothrium 0.70, breadth 0.56; maximum length of hook 0,11. 



1905, August 8 : Few. August 21 : 1. 



Dasyhatis centrura. 



Several found in a vial which contained a considerable number of 

 A. paulum^ collected from a large sting ray, September 1, 1903. I 

 find in my notes made at the time of collecting, that, on account of 

 the large amount of material obtained on that date, the small forms 

 were not separated carefully. Length, mounted in balsam, 15 mm. ; 

 length of hooks 0.12 mm. 



ACANTHOBOTHRIUM PAULUM Linton. 



Plate 4, fig. 32. 



1S90, pp. 816-819, pi. 8, figs. 1-7. 



1900, p. 275. 



1901, pp. 433, 434. 



1905, pp. 346, 348, 349, fig. 126. 

 1910a, p. 10. 

 1911, p. 585. 



The cestode recorded in preliminary reports: 1907e (p. 113), and 

 1908& (p. 163), as A. paulum proved to be a new species, and was 

 described under the name A. hrevissimum, 1908& (pp. 173-4; pi. 4, 

 figs. 26-29). 



