132 BULLETIN OF THE BUREAU OF FISHERIES. 



EXPLANATION OF PLATES. 



KEY TO LETTERING. 



b, bothrium. i/i, muscle tissue. 



hi, blastocyst (pleroccrcus). o, accessory bothrial organ. 



c, cyst. j>. proboscis. 



ca, calcareous body. sc, scolex or larva. 



ch, contractile bulb of proboscis. sh, proboscis sheath. 



ct, connective tissue. st, beginning of strobile. 



PLATE I. 



Fig. 1. Specimen of butterfish (Poronotus friacanthu.^) laid open to show cysts of Otobothrium a-enacolle. 



Tlie principal regions of infection are shown somewhat diagramaticalh'. The number of cysts shown 



in the sketch is far less tlian may be seen in a badly parasitized fish. Sketch made from a fish 22 



centimeters in length, from Barnegat, N. J. 

 Fig. 2. From life. Cluster of cysts from the butterfish. The cluster measured 2.1 by L2 milhmeters in the 



two principal diameters. The scoleces were active, their average length about 1 millimeter. 

 Fig. 3. A blastocyst from cluster shown in figure 2, compressed so as to show the distinctive features of the 



species: length of larva 0.8 millimeter. 

 Fiii. 4. .Another cyst from same host. The lilastocyst, which does not completely fill the cyst, measured 1.24 



by 0.8 millimeter in the two diameters. 

 Fig. .5. Blastocyst of figure 4 removed from the cyst. The head and pait of the neck of the scolex is emerging 



from the blastocyst and the proboscides are everted. 

 Fig. 6. Cyst with three blastocysts containing scoleces, from serous coat of intestine of squeteague {Cynoscion 



)-egalis). The walls of the cyst were transparent : blastocysts and scoleces active. Cyst 1.8 by 1.12 



milhmeters in the two diameters. 



PLATE 11. 



Fig. 7. Cyst, blastocyst, and scolex from butterfish, life. Diameter of cyst, 0..5 millimeter. 



Fig. 8. Blastocyst with scolex emerging — removed from cyst shown in figure 7. 



Fig. 9. Sc«lex (larva) removed from blastocyst. 



Fig. 10. Part of bothrium highly magnified, showing the accessory organs retracted. 



Fig. 11. One of the accessoiy organs, everted, still more highly magnified. 



Fig. 12-16. Dift'erent views of proboscides highly magnified. Figures 12 and 13 are views of portions of the 

 proboscis near the base. The .sketches were made with the aid of a camera lucida, 1-inch eyepiece 

 and one-twelfth objective, and represent an enlargement of about 720 diameters. 



Fig. 17. Cyst, blastocyst, with scolex and muscle tissue of host, compressed; sketched from specimen mounted 

 in balsam, X about 60. 



Fig. is. Section of mu.scle tissue with fifteen cysts, X about 6. The nniscle fibers arc cut transversely in the 

 upper and longitudinally in the lower part of the figure. 



Fig. 19. Section of muscle tissue with ten cysts, X about 60. a, empty cysts; blastocysts with larvip appear in 

 other sections of the series; d, neck of scolex cut transversely, showing the four probo.scides ; c, scolex cut 

 nearly longitudinally: /, bothria cut nearly transversely: </, section passes through the bothria and two 

 of the contractile bulbs nearly longitudinally: the neck of the larva has been bent and is largely missing 

 from this section: h, diagonal section of neck of larva — at one end of .section the proboscides are cut 

 transversely, at the other two of them appear but cut longitudinall}-; i, section shows blastocyst but 

 misses the larva, which may be seen in another section of the series. 



