NEW ACTINIAKS FROM BRITISH COLUMriA. 965 



representing the small elevations already described as scattered 

 over the entire surface of the column. The tentacles seem to have 

 been of a paler colour than the upper part of the column and 

 marked by four or five rings of a more or less intense brownish 

 red (fig. 2). The conch ular processes seem to have been of the 

 deeper shade, with paler apices. 



Structure. — The column mesoglosa is much thicker than the 

 ectoderm and is of a finely fibrillar structure, cells being scattered 

 among the fibrils. There are no ectodermal muscles, but 

 associated with the presence of ectodermal gland-cells there is a 

 "well-defined layer of nerve-fibres. The adhesive oigans appear 

 in sections as elevated areas of the ectoderm,' composed of slender 

 cells considerably longer than those of the adjacent ectoderm ; 

 the areas contain no gland-cells and, consequently, appear much 

 paler than the general ectoderm in stained preparations. In 

 structure, therefore, the organs dififer from typical veirucse only 

 in being elevations of the surface instead of depressions. The 

 endodermal musculature is supported on short simple pi-ocesses, 

 and towards the distal poi-tion of the column it becomes weaker, 

 the cells being arranged in an almost simple layer, and there is 

 no indication of a sphincter. 



The musculature of the tentacles and disk is very moderately 

 developed, and there are no muscle-fibres on either the ectodermal 

 pr endodermal surface of the stomatodeeum. The stiucture of 

 the siphonoglyph is quite characteristic. Its ectoderm is much 

 higher than that of the rest of the stomatodseum and destitute of 

 gland-cells. The surface bears verj' numerous strong cilia and is 

 provided with a distinct cuticular layer, beneath which the nuclei 

 of the cells are arranged in very many layers, the basal portion of 

 the epithelium containing but few, and appearing as if composed 

 of a very fine reticulum, which is traversed by a band of nerve- 

 fibres. The endoderm is also much higher than it is over the 

 rest of the stomatodseum and its basal portion is also reticular in 

 structure, though somewhat coai'ser than the ectoderm. The 

 mesogloea also difters from that of the general stomatodteum, its 

 ground- substance being almost homogeneous and assuming a 

 clear blue tint with hsematoxylin-erythrosin, while elsewhere the 

 colour is decidedly violet. The fusion of the lips, mentioned 

 above, is merely an epithelial union ; indeed, it appears to be 

 due to adhesion of the cuticular layers of the two adjacent 

 surfaces. 



The mesenteries are arranged in ten pairs, six of which 

 are perfect, the remaining four pairs occupying the lateral 

 and sulco-lateral interspaces. Of the perfect mesenteries, two 

 pairs are directives, and all have well-developed difixise muscle- 

 pennons (fig. 4) consisting of sti'ong though but slightly 

 branched lamellae. A well-marked pai'ieto-basilar muscle is also 

 present forming usually a slight fold. The reproductive cells 

 could not be distinguished in the individuals examined, but 

 the endoderm of the mesenteries in the region proximal to the 



