114 BULLETIN OF THE BUREAU OF FISHERIES. 



In these cases enormous numbers of cysts were seen in the muscles. They were most abundant on the 

 ventral side of the vertebral column, between the subvertebral spines. They were also scattered through 

 the dorsal region, lying deep among and near the dorsal vertebral spines. The cysts are small, oval, about 

 1 mm. in length and somewhat less in shorter diameter. * * * Dimensions of larva in millimeters: Length, 

 0.7; bothria nearly circular, 0.3 in diameter; diameter of neck, 0.1. Contractile bulbs very short. 



Since the foregoing record was made I have found this parasite in a number of 

 different hosts at Beaufort, N. C. a , Woods Hole, Mass., and in Bermuda. Details 

 of these finds are given in my reports on these localities and a list of the hosts is 

 given later in this paper. 



Beginning with August 8, 1904, a systematic search was made for these 

 parasites in the flesh of thebutterfish and examinations were made on nine different 

 dates that season, the last on October 12. The fish came from Buzzards Bay, near 

 the village of Woods Hole; Nomans Land, a small island which lies some five miles 

 at sea off the western end of Vineyard Sound : Montauk, Long Island, and Barnegat, 

 X. J. In all, 188 fishes were examined, of which only one-half of 1 per cent were 

 without parasites in the flesh, and 75 per cent were badly infested. Prior to August 

 8 a lew butterfish had been examined, but search was made only on and in the 

 viscera. Of these examinations I find in my notes on the dates July 20 and 25 

 mention of finding on the viscera small cysts containing living blastocysts, which, 

 though not sufficiently developed for certain identification, are very probahly 

 Otobothrium crenacoUe. It is somewhat surprising in the light of the subsequent 

 discovery of the prevalence of this parasite in the flesh of the butterfish, and in the 

 intestinal walls of many other fish, that the viscera of the butterfish should be so 

 free from it. 



During the summers of 1905 and 1906 the search for parasites was continued 

 and a total of 331 fish were examined. Of these 42 per cent were badly infested, 

 and only 11 per cent revealed no parasites. 



DESCRIPTION OF SCOLEX, CYST AND BLASTOCYST. 



Scolex. — In most cases where the cysts were opened the scoleces were found 

 to l>e sufficiently developed to admit of identification. So far as can be determined 

 from the scolex alone the species is Otoboihrium crenacoUe. The bothria agree 

 closely with those of the adult as found in the spiral valve of the hammerhead. 

 The proportions of the head and neck, the blunt salient angles, and the crenulate 

 holder of the posterior end of the neck produced by the diverging posterior ends 

 of the contractile bulbs are all in close agreement with similar features in the adult. 

 The hooks on the proboscides, although seen to present considerable variety, are not 

 in disagreement with what I have observed in the adult (fig. 12-16). The peculiar 

 accessory organs on the bothria were found to be present in all scoleces that possessed 

 well-developed proboscides, and they were found to have longer bristles than was 

 noted in the original descriptions (fig. 10, 11). They are eversible, and together 

 with the proboscides often showed signs of life where the scolex was otherwise 

 quiescent. 



" Linton, Parasites of fish.es of Beaufort, North Carolina. Bulletin Bureau of Fisheries, vol. xxiv, 

 1904, p. 32] -428, pi. i xxxiv. 



