526 OLWEN M. REES. 



and are very small near the base, but get large in the region near the 

 retractor muscle. 



Many of the mesenteries which are incomplete develop sex organs 

 and mesenterial filaments. The latter have three distinct lobes. 



The stomatodseum is very long and iji cross section is triangular in 

 shape in all the specimens that I examined, because in each case the 

 specimen was more or less contracted. This triangular shape is due 

 probably to the equal pressure exerted by the mesenteries on the cylin- 

 drical oesophagus during contraction. The wall is raised into numerous 

 folds, the number and position usually corresponding to the number 

 and attachment of the mesenteries reaching the oesophagus. The ecto- 

 derm of this region is characterised by its large number of spindle-shaped 

 granular gland cells. The mesogloeal process in each fold is unbranched 

 and generally pointed at the tip. 



Oral stomatopores were found in all the complete septa. These are 

 very small and lie between the retractor and the parieto-basilar muscles, 

 as in S. viduata. The tentacle (Fig. 2) is characterised by a remarkably 

 strong longitudinal muscle in the ectoderm. The mesogloeal folds are 

 very deep, are branched, and numerous. There is a distinct endodermal 

 muscle, the endoderm is folded and the zooxanthellse are very numerous. 

 Gland cells and nematocysts are present in the ectoderm of the stem and 

 tip of the tentacle. 



Sagartia ornata (Holdsworth). 



The specimen here described was found attached to the under surface 

 of a stone in a pool on the reef near the Castle, Aberystwyth, just below 

 ordinary low-water mark, on October 3rd, 1913. This species has been 

 previously recorded from the same and from adjacent localities. 



Form : base exceeding column and irregular in outline ; the specimen 

 was never seen fully expanded in the day time and only partially so at 

 night. Soon after its capture it left the stone and attached itself to the 

 vessel in which it was kept, and there remained firmly attached and 

 much flattened. 



Column, according to Gosse, " minutely corrugated, studded on the 

 upper half with ' suckers,' more numerous as they approach the summit." 

 A fair amount of mucus was given off from time to time. The tentacles 

 appear to be about 96, probably arranged in the following cycles : 

 6+6+12+24+48. They are rather short and obtuse at the tip. 



Disk (seen only by artificial light), mouth appeared slightly raised, 

 lips somewhat thickened. QEsophageal grooves could be distinguished. 

 Acontia, one was seen emitted from the mouth. 



