The nudibranch family Dironidae. 535 
Explanation of Plates. 
All of the figures of Plates 30—32, with the exception of Fig. 2 of 
Plate 30, were drawn by Mrs. OLıve H. MacFaArLaAnD. Fig. 2 of Plate 30 
was drawn by Mrs. LouIsE B. NAsH. The ABBE Camera Lucida was 
used in all drawings except Fig. 1 and 2 of Plate 30 and Figs. 21—23 of 
Plate 32. 
Plate 30. 
Fig. 1. Dirona pieta MacF., painted from life. 5:1. 
Fig. 2. Dirona albolineata MAcF., painted from life. 5:1. 
Plate 31. 
Figs. 1—10, Dirona pieta MacE. 
Fig. 1. Three median teeth from above. 220:1. 
Fig. 2. Three median teeth in side view. 220:1. 
Fig. 3. Median tooth in ventral view. 220:1. 
Fig. 4. Second lateral tooth, inner face. 220:1. 
Fig. 5. Mandibles from right anterior side. w wing. h hinge liga- 
ment. m masticatory portion. 12:1. 
Fig. 6. Inner face of left mandible. :» wing. A hinge ligament. 
c ehitinous band connecting the two mandibles. m masticatory portion. 
lass |: 
Fig. 7. Outline of right mandible from external surface as seen by 
transmitted light to show the three thickened portions I, 2, 3, radiating 
from and strengthening the hinge region. 
Fig. 8. First lateral tooth, dorsal view. 350:1. 
Fig. 9. First lateral tooth, ventral view. 350:1. 
Fig. 10. First lateral tooth, inner face. 350:1. 
Figs. 11—19, Dirona albolineata MAcF. 
Fig. 11. Two median teeth from above. 220:1. 
Fig. 12. Median tooth, side view. 220:1. 
Fig. 13. First lateral tooth from above. 220:1. 
Fig. 14. First lateral tooth, inner face. 220:1. 
