82 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. G4. 



distribution, seen in whole mounts as a dense glandular mass along 

 the lateral margins, but also constituting a layer surrounding the 

 inner core of the segment which contains tlie testes. 

 Type.— 11.^.^ M., Helm. Coll. 7710. 



Adult stage. 



Vulpecula 'marina. 



1912, August 7: 4 strobiles with scoleces, and 5 free proglottides: 

 longest 33 mm.; length of scolex, 6, breadth through bothria 2; 

 posterior proglottis, length 2.5, breadth 1; posterior segments rec- 

 tangular, contracting when placed in killing fluid; ova subglobular, 

 with very thin shells, diameter about 0.048. Diameter of proboscis, 

 :ii balsam, basal bookless portion 0.072, portion near base bearing 

 minute hooks, including hooks, 0.066, a short distance in front of 

 portion bearing minute hooks, excluding hooks, 0.051, including 

 hooks, 0.12. 



Larval stage. 



Xiphias gladius. 



1911, July 10: Collected by Vinal N. Edwards, who, noticing the 

 presence of parasites in flesh attached to a piece of backbone of a 

 swordfish at the fish market, brought them to the laboratoiy. There 

 was one scolex with an elongated plerocercus still attached, 40 mm. 

 in length, increasing to 50 mm. when transferred to a slide. Beside 

 this there were two fragments 27 and 12 mm. in length respectively. 

 They were all embedded in muscular tissue near the vertebrae. 

 Upon pressure the scolex with its short neck separated from the 

 plerocercus. It was fixed under pressure with the proboscides in 

 greater part extruded. 



Upon comparing the scolex with that of the adult form from the 

 thrasher shark, the agreement in detail in the peculiar character of 

 the hooks was found to be so close that there seemed to be no room 

 for doubt concerning their specific identity. 



Dimensions of scolex, adult from Vulpecula marina, larva from Xiphias gladius; 

 specimens mounted in balsam, and more or less flattened. 



Adult. Larva. 



Length of bothrlum 0. 63 0. 77 



Breadth, bothrium 0. 72 0. 84 



Diameter of neck 0. 49 0. 67 



Length of contractile bulb 0. 5G 0. 56 



Diameter, contractile bulb 0. 14 0. 21 



Length of proboscis, approx 2. 80 2. 00 



Diameter of unarmed basal portion 0. 075 0. 066 



Diameter, median, including hooks 0. 12 0. 12 



Diameter, median, excluding hooks 0. 054 0. 054 



Length of large basal hooks 0. 12 0. 105 



Length of smallest hooks, in front of large basal hooks 0. 006 0. 006 



Maximum length of most al)undant slender hooks 0. 075 0. 075 



