18 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
D. Stages 3.1-3.5 mm. (early cryptacanthiform stage). 
Fig. 6. Specimen with pedicle valve partially removed to show loop and 
the small hood seen from the ventral side, * 8, paratype U.S.N.M. 
No. 127206k. 
Fig. 7. Partial view from the dorsal side showing loop with small early 
hood, 8, paratype U.S.N.M. No. 1272033. 
Fig. 8. Another specimen showing trace of early hood, X 8, paratype 
U.S.N.M. No. 127203h. 
E. Stages 3.6-4.0 mm. (cryptacanthiform stage). 
Fig. 9. Specimen with part of brachial valve stripped off to show upper 
part of hood, X 8, paratype U.S.N.M. No. 1272031. 
F. Stages 4.1-4.5 mm. (cryptacanthiform stage). 
Figs. 10, 11. Side and partial side views of a specimen showing the small 
early hood and its slender attachment to the descending branches, X 8, 
paratype U.S.N.M. No. 127204h. 
Fig. 12. Side view of another specimen showing hood with long pos- 
terior extension, X 6, paratype U.S.N.M. No. 127204Cc. 
G. Stages 4.6-5.0 mm. (cryptacanthiform stage). 
Figs. 13, 14. Ventral and side views of an exceptionally well-preserved 
adult loop, 6, paratype U.S.N.M. No. 127204t. (For additional 
views of this specimen see pl. 1, I, figs. 26 and 27.) 
Fig. 15. Imperfect loop from dorsal side, 6, showing jugum, paratype 
U.S.N.M. No. 127203x. 
H. Stages 5.0-6.0 mm. (late cryptacanthiform stage). 
Fig. 16. Loop seen in side view and showing long attachment to de- 
scending branches and septumlike extensions posteriorly, < 6, paratype 
U.S.N.M. No. 127204q. 
Figs. 17, 18. Two anterior views of a specimen showing the expanded 
hood, <6, paratype U.S.N.M. No. 127204-0. 
I. Stages 7.1-9.0 mm. (late cryptacanthiform to early glossothyropsiform 
stages). 
Fig. 19. Adult loop seen from the laterodorsal view and showing the 
jugum, and the descending lamellae with their rows of spines, X 6, 
paratype U.S.N.M. No. 127204]. 
Fig. 20. Specimen seen from the posterior to show the posterior side of 
the hood, X 4, paratype U.S.N.M. No. 127205). 
Fig. 21. One of the largest specimens in the collection showing the de- 
scending lamellae from the dorsal side and absence of a jugum tying 
the branches together, < 6, paratype U.S.N.M. No. 127205h. 
