Plate 40 



Fig. 1. Eryliii cornutus. a, b, ortliodiaenes in side view, c, cladoine seen from 

 below. X90. 



2. Erylus cornutus. a, sterraster in edge view; b, same in face view. 



Rays shown only over a part of the surface of the sterraster in 

 both figures. X240. 



3. Geodia philippinensis. From a vertical section showing a dichotriaene 



in the ectochrote accompanied by two anatriaenes and a protriaene ; 

 dermal membrane indicated by small asters ; ectosomal oxeas radial 

 to dermal membrane; outermost sterrasters shown. X90. 



4. Geodia philippinensis. a, dermal oxyasters ; b, choanosomal oxyaster. 



X600. 



5. Geodia philippinensis. Cladomes of two dichotriaenes in natural posi- 



tion in the dermal membrane. X90. 



6. Sidonops microspinosa. Pore area with open pore. Spherasters 



crowded round edge of pore. X140. 



7. Geodia sparsa. a. plagiotriaene from the side. X160; b, projecting 



protriaene with prolonged rhabdome. X300. 



8. Geodia sparsa. Part of dermal surface, showing distribution of 



plagiotriaenes ; also sterraster-free tracts with open pores. X45. 



9. Sidonops microspinosa. Vertical section through a pore area and 



afferent chone canal, p. c, oblique pore canals, probably four, 

 marked by spherasters ; r. a. c, radial afferent chone canal marked 

 by a streak of oxyasters; ch. c, inner end of chone; s. c, subcortical 

 crypt. X140. 

 10. Sidonops microspinosa. Vertical section through an oscular area. 

 p. o. e., perioscular elevation ; r. e. c, radial efferent chone canal, 

 marked along most of its extent by a streak of oxyasters, but above 

 by a dense accumulation of spherasters indicating the position of 

 the osculnm, o, which is actually closed ; ch. c, inner end of chone ; 

 *. c, subcortical crypt. X85. 

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