6 PROCEEDINGS OF THE NATIOITAL MUSEUM. vol.01. 



on stalk-like projections of the bothria. Also the front end of the 

 scolex between the bothria was actively extended into a sharp-pointed 

 cone which retracted to a rounded eminence when at rest. The stro- 

 biles measured about 30 mm. in length. Proglottides began about 

 8 mm. back of the scolex. The maximum diameter of the scolex was 

 about 2 mm. and the length about the same. There were no mature 

 segments. 



2. ISURUS DEKAYI. 



August 9, 1905. A mackerel shark, examined on this date at Woods 

 Hole, contained lenses of fish in the stomach and a broken spine of 

 /Squalus acanthias embedded in the stomach wall. Nineteen cestodes, 

 similar to those found in the maneater shark, were found in the spiral 

 valve. These were from 10 to 160 mm. in length, living, although the 

 longest alcoholic specimen is only 65 mm. in length. The first distinct 

 segments were about 20 mm. back of the scolex. The first segments 

 very indistinct, succeeding ones very short, ultimately becoming 

 squarish, then longer than broad. There were no ripe segments. The 

 bothria were leaf-like, very mobile and assuming a great variety of 

 shapes, but contracting into a cauliflower-like structure when placed 

 in alcohol. 



August 21, 1905. The spiral valve of a mackerel shark taken at 

 Menemsha Bight, which had been in formaldehyde for a few days, was 

 examined on this date. No note had been made of the stomach con- 

 tents, but the beak of a squid was found in the spiral valve, along with 

 21 scoleces, and many fragments of strobiles similar to those col- 

 lected on the 9th, but with rather larger scofeces. 



B. Larvat, stage. 



Larval cestodes belonging to the genus Phjdlobothrium are com- 

 mon in the squid of the New England coast, both the northern 

 species, Ommastreplies illecehrosa^ and the southern species, LoUgo 

 pealii. There are good reasons for thinking that these represent an 

 immature stage of the species described in this paper. 



In 1887 Leidy^ described larval cestodes from the squid 0. illece- 

 hrosa, under the name Taenia loUginis, and again,^ under the name 

 Tetrabothrium loliginis. In the latter account he designates the 

 cestode as the scolex of Tetrabothrium Rudolphi, or Phyllohothrium 

 Van Beneden. 



P. J. van Beneden, in 1870,^ published a description of a cestode. 

 under the name Phyllohothrium delpJmii Ed. van Beneden, of which 

 his son had collected the material in 1868. The worms were found 



1 1'roc. Acad. Nat. Sci., Phila., 1887, p. 24. 



2 Idem, 1890, p. 418. 



3 Bull. Acad. Belg.. vol. 29, pp. 115-117. 



