198 BULLETIN OF THE BUREAU OF FISHERIES. 



EXPLANATION OF PLATES. 



[Drawings by G. T. Kline.] 



PLATE VI. 



Fig. I. Gravid female of Ptychobranchus phaseolus. Actual length 96 mni. 

 Fig. 2. Gravid female of Lampsilis subrostrata. Actual length 50 mm. 

 Fig. 3. Gravid female of Symphynota complanata. Actual length 170 mm. 



PLATE VII. 



Fig. 4. Gravid female of Dromus dromus. Actual length 57 mm. 

 Fig. 5. Gravid female of Quadrula ebena. Actual length 98 mm. 

 Fig. 6. Gravid female of Lampsilis recta. Actual length 122 mm. 

 Fig. 7. Gravid female of Obliquaria reflexa. Actual length 55 mm. 

 Fig. 8. Gravid female of Cypiogenia irrorata. Actual length 38 mm. 



PLATE VIII. 



Fig. 9. Hooked glochidium of Symphynota costata, anterior end view. For measurements see text 

 figure I. 



Fig. 10. Hooked glochidium, as above. Lateral view of living specimen. 



Fig. II. Axe-head glochidium of Lampsilis (Proptera) alala, anterior end view. For measure- 

 ments see text figure i . 



Fig. 12. Axe-head glochidium, as above. Lateral view. 



Fig. 13. Hookless glochidium of Lampsilis subrostrata, lateral view. For measurements see text 

 figure I. 



Fig. 14. Hookless glochidium, as above. Posterior end view. 



Fig. 15. Hookless glochidium, as above. Ventral view. 



Fig. 16. Detail of a conglutinate of Lampsilis ligamentina. The glochidia, still inclosed in the 

 membranes, are less crowded together than those of figure 17, and are embedded in a mucilaginous 

 matrix. 



Fig. 17. Detail of a conglutinate of Obliquaria reflexa, showing the membranes closely pressed and 

 adhering together. 



Fig. 18. Young mussels (Lampsilis ligamentina) one week after liberation from the fish, showing 

 various positions assumed in crawling, the ciliation of the foot, and the new grov^^th of shell. 



PLATE IX. 



Fig. 19. Fin of a carp about 3 inches long, 7 days after infection with glochidia of Anodonta cata- 

 racta, showing complete failure of the overgrowth of fin tissue in all places where the glochidia are greatly 

 crowded. See explanation in the text, p. 159, of the conditions along the upper margin. 



Fig. 20. Tip of an over-infected fin, as above, 12 hours after infection, showing no appreciable over- 

 growth because of the crowding. The shadows represent glochidia upon the under surface. 



Fig. 21. Pectoral fin of a carp, as above, 3^ hours after infection; an optimum infection. 



Fig. 22. Ventralhalfof caudal fin of a carp, as above, 24 hotirs after infection; an optimum infection. 



Fig. 23. Tip of fin, as above, 32 days after infection. The shadows represent glochidia upon the 

 under surface. The infection is less than the optimum. The glochidia were well overgrown and all 

 alive when the fish was killed. 



Fig. 24. Young Symphynota costata, attached by only a shred of tissue and about to drop from the 

 fin after a parasitism of 74 days. 



