54 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 64. 



in July, 1903, The same forms had been found in the flesh of the 

 needle-fish, T. raphidoma, at Beaufort, N. C, in August, 1901, and 

 recorded as Otohothrium^ species. 



I have found the adult stage of this tetrarhynch in the hammer- 

 head shark, Cestracion zygaena^ on two occasions, at Woods Hole, 

 Massachusetts. 



On the evening of August 2, 1908, a hammerhead shark, taken off 

 Nomansland by Captain J. W. Fuller, of Provincetown, was brought 

 to the laboratory of the United States Bureau of Fisheries. It was 

 not opened until the following morning. The stomach contained 

 fragments of fish and squid, large numbers of lenses, both of fish 

 and squid, and a few " pens " of squid. 



The cestodes, of which two species were found in the spiral valve, 

 were somewhat macerated, especially at the anterior ends. Six of 

 the larger cestodes, with free, ripe proglottides, were recognized as 

 the adult stage of O. penetrans. The longest of the strobiles meas- 

 ured 160 mm. before, and 130 mm. after having been placed in 

 alcohol. Length of scolex, 5 mm., breadth, in front, and at posterior 

 end, near base of contractile bulbs, 3.25, breadth in middle, 2; free 

 proglottides, length 8, breadth 4.5 ; eggs, 0.036 by 0.027. 



The scoleces were not in good condition, the bothria were much 

 crumpled, and the pits, characteristic of this genus, could not be 

 made out, but all features present were in agreement with the genus 

 Otobothriwn^ and the hooks on the proboscides, so far as seen, agreed 

 with the species O. penetrans. 



On August 18, 1913, a single specimen of this cestode was obtained 

 from the spiral valve of a hammerhead shark. The shark measured 

 285 centimeters in length. The stomach contained numerous lenses 

 of large fish, and a considerable quantity of oil. 



The following measurements were made of material before it had 

 been placed in preservative : Length of strobile, 103 mm. ; scolex, 

 length 4, breadth, anterior, 2.5, posterior, 3.5 ; last proglottis, length 

 5.5, breadth, 3.5; largest free proglottis, length, 8.5, breadth 3.5. 

 There were also found twelve free proglottides, one short fragment 

 of three segments, and a fragment of the posterior end of a strobile 

 measuring 55 nrni. in length. The strobile was flat and thin, the 

 scolex subcylindrical. The bothrial pits were not made out at the 

 time of collecting, but can be seen in the stained and mounted scolex. 



A specimen of this species was collected by Dr. Davenport Hooker 

 from CarcharhinvR commersonii. at Tortugas, on July 26, 1907, and 

 brought to me at Woods Hole by Dr. A. G. Mayor. 



(U.S.N.M., Helm. Coll. 7698.) 



In the original description of the species the statement that tlie 

 bothria are marginal is misleading. It was probably written from 

 the appearance of cross sections of the scolex made through the 



