The Actiiiiae of the Plate Collection. 283 



smaller ridges alternating with these larger ones. The tentacles were 

 sliort and pointed and were somewhere in the neighbourhood of 100, 

 probably 96, in number. No bulbous enlargements of their bases 

 were present. The disc and mouth were completely concealed in 

 all the specimens. 



The larger individuals measured 0.8 to 1.0 cm in height with 

 a basal diameter varying from 1.6 to 2.0 cm. The accompanying 

 label States that they were of a redbrowai color in life and the same 

 coloration is retained by the preserved specimens. The smaller indi- 

 viduals were paler than the larger ones, the smallest, indeed, being 

 almost colorless. In the larger ones the color is a dark seal-brown 

 throughout the entire extent of the scapus and the tentacles have 

 the same color. The capitulum was colorless and in some specimens 

 in which the cuticle has been rubbed off from the tubercles the 

 exposed surface is white, indicating that the color of the scapus is 

 due to a large extent to the cuticle which covers it, although a 

 brown pigment also occurs in the ectoderm, giving the tentacles 

 their color. 



Structure. The mesogloea of the columu wall is thicker than 

 the ectoderm and is almost homogeneous in texture. Bays of ecto- 

 derm extend down into it at irregulär intervals, giving in sections 

 the appearance of cavities in the mesogloea lined with brown pig- 

 mented cells. The tubercles are solid elevations of the mesogloea. 

 The circular muscles are feeble, there being but few scattered 

 slender processes of mesogloea for their support and in the upper 

 part of the column even these are practically wanting. The sphincter 

 (Fig. 73) is well developed and triangulär in section. It is conflned 

 to the capitular region and is reticular in structure, the meshes 

 being elongated transversely in the upper part, while below they 

 are more rounded and more separated from one auother; there is 

 no layering. 



The longitudinal muscles of the tentacles and the radial muscles 

 of the disc are moderately developed and entirely ectodermal in 

 Position. The stomatodaeum is longitudinally ridged and is provided 

 with two rather shallow siphonoglyphs. 



The mesenteries are arranged hexamerously in four cycles, those 

 of the.fourth cycle being very small and destitute of mesenterial 

 filaments. The musculature of the mesenteries is rather weak, the 

 pennon forming but a slight elevation on the surface (Fig. 74), the 

 parieto-basilars not forming any fold, while the basilars were in- 



