140 
Wisconsin Academy of Sciences, Arts, and Letters. 
EXPLANATION QF PLATE XI. 
Fig. 7. Youngest stage. D. 2. The first three appendages, 
first antenna, second antenna^ mandibles, have been 
drawn from one side only and the setae omitted. 
Of the fourth appendage both right and left have 
been drawn. 
Fig. 8. Chitinous supporting framework of the legs. A. 2. 
A. anterior. D. dorsal. 
Fig. 9. Diagrammatic view to show the relation of the vari¬ 
ous parts to each other. S. G., shell-gland. E., 
eye. A. G., adhesive gland. B., brain. IT. L., 
upper lip. L. L., lower lip. Ovary dotted. The 
different regions of the alimentary tract have not 
been lettered. They can easily be distinguished as 
can the different parts of the nerve cord. 
Fig. 10. Copulatory apparatus. D. 2. D., dorsal. A., an¬ 
terior. C, connecting piece. B. B., two halves of 
basal piece. E., Clasping piece. F,, probable cop¬ 
ulatory duct. 
Fig. 11. Four outline views of shells of females. All A. 3, 
D., dorsal. A., anterior. 
Fig. 11. Three similar views of males. A. 3. 
