262 J- Playfair Mc Murrich. 



tlie regions where the ectoderm has been macerated away a decided 

 dark coloration. This Iquique specimeii is stated in the label which 

 accompanies it, to liave been of a blue color during- life. 



Strnctnre. The tubercles of the colmnn are evag'inations of 

 the wall in the intermesenterial Spaces and each contains a cavitj' 

 continuous with that of the space in whose wall it occnrs. In the 

 intervals between snccessive evaginations the mesogloea of the 

 cohimn wall is moderately thick and is thrown on its inner siirface 

 into well marked branching processes for the support of the circnlar 

 mnsculatnre, bnt the mesogloea of the evaginations is on the con- 

 trary thin and its inner snrface is smooth. The endoderm every 

 where contains dai-k pignient grannies, which are less plentiful in 

 the lig'hter colored individuals than in the others, and it seems 

 probable that the g'reat variety observed in the coloration of living 

 specimens may be due to a diifnse pigment located in the ectoderm. 

 No iiematocysts were detected in the ectoderm of the tubercles, bnt 

 that of the acrorhagi was densely crowded with them (Fig. 39). 



The sphincter is a well-developed representative of the diffuse 

 endodermal type, having the appearance shown in Fig*. 39. In some 

 individuals the lamellae are more branched than in that from which 

 the figure was drawn, but the general form and development were 

 about the same in all the specimens examined. 



The tentacles have their mesogloea longitndinally ridged npon 

 the outer snrface, the fluted appearance mentioned above being thus 

 produced. Their longitudinal mnsculatnre is entirely ectodermal 

 (Fig. 40), as is also the radial mnsculatnre of the disc (Fig. 41), the 

 latter, however, being somewhat stronger than the former and 

 supported on fairly high but unbranched mesogloeal processes. 



The stomatodaeum is provided with numerous longitudinal ridges 

 and possesses two siphonoglyphs. The endoderm of the latter seems 

 to be much thickened, the thickening-, however, being due to numerous 

 fine fibrillar processes which arise from the mesogloea and support 

 the endodermal cells, an arrangement which I have already described 

 as occurring in Crihrina cleganfissima (1901). On the ectodermal 

 snrface of the mesogloea of the siphonoglyphs small and somewhat 

 widely spaced simple processes occur for the support of a longitudinal 

 ectodermal musculature, which was either absent or consisted of 

 only a few scattei'ed fibres over the general snrface of the stomato- 

 daeum. 



The pairs of mesenteries were 192 in number in the largest 



