Plate II. 



From specimeus iu the author's collection. 



1. Upper view of a section of a row of poral piecesj showing collapsed 

 tentacles in the poral openings. 



2. Normal condition of the ambulacral integument. 



3. Plications of integument covered by little scales, the larger scales at 

 the summit standing upright. 



4. Section through a row of poral pieces, showing the tentacles ex- 

 panded. 



5. View of the normal condition of the ambulacral integument. 



6. Longitudinal section tlirough the ovarian tubes. 



7. Irregular expansion of the integument. 



8. Transverse section through an ambulacrum, showing lancet piece with 

 the nervous channel, poral piece, vascular duct (blue), hydrospiric tube 

 with its internal plications, and between them the ovarian tubes. The 

 space at either side of the vascular duct, colored yellow, was filled with a 

 clayey substance. 



9. Base portion of the deltoid piece with the lateral expansion removed to 

 show the grooves in which the hydrospiric plications rest; also the lateral 

 orifices of the nervous channel. 



10. Highly magnified view of the anal opening of tSaccohlnstus. 



11. Section showing the looping of the hydrospiric membrane on the inner 

 side of the calvx. 



