PLATE 2. 



Figs. 17 to 19. — BoUenia echinata. 

 Fig. 17. The whole animal from which the description is mostly drawn, 



x- 1. 

 Fig. 18. One side of a branchial fold of the specimen shown in figure 17. 

 Fig. 19. The whole animal, a specimen from near Point Loma, that shown 



in 17 being from near Point Pinos. X 4. 



Figs. 20 and 21. — Cuholufi pyraniidalis. 

 Fig. 20. Side view of the whole animal, X 1. 

 Fig. 21. Dorsal view same specimen, X 2. 



Figs. 22 and 23. — Microcosmus transveisus. 

 Fig. 22. Side view of the whole animal, X 1. 



Fig. 23. The same specimen removed from the test and the mantle cut oi)en 

 and laid back, X 1. 



Figs. 24 to 29. — Benthascidia micJtaelseni. 



Fig. 24. The column with holdfasts, X 2. 



Fig. 25. A small tuft of the holdfasts, X 12. 



Fig. 26. Sonje of the mantle musculature in the region of the supposed 

 branchial orifice. 



Fig. 27. The digestive apparatus and sexual organs, X 1. 



Fig. 28. Outline of the digestive tract, showing the tuft of filiform appen- 

 dages near the esophageal orifice and a fragment of the 

 branchial membrane attached. 



Fig. 29. A portion of the tentacular circlet and hypophyseal region seen 

 from within. 



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