CHESTKR. — STRUCTURK OF PSKHDOPLEXAIIRA CRASSA. 



745 



and its endoderinal cpitlu'liuin is continuous with that of the chanihcr. 

 The stoniodaeuni (Fig-. 1, 77, .s7//k/.) is Umv:, reachin-,' when the polyp is 

 expanded, nearly if i\()t (juite to the level of the surfaee of the eoe- 

 nenehynia; it is l)roadest in the dorso-ventral plane and has at its 

 ventral angle a prominent siphonoglyph (Fig. 2, .v//>//.), which is not 



Fig. li. Calcareous spicules: X 90. 1-4, white spicules of outer cortex 

 region; 5-7, purple spicules from the region of tlio longituclinal canals. 



visible on the disk, but* reaches nearly to the deep end of the stonio- 

 <laeum. The structure is that usually found in the siphonoglyph of 

 Alcyonaria. A transverse section through the stomodaeum is shown 

 in Figure 2. The siphonoglyph is always ventral, and the longitudi- 

 nal nuisdes of the eight mesenteries, as is usual in Alcyonaria, are 

 located on the ventral sides of the mesenteries. Figure 3 shows a 



