88 THE VOYAGE OF H.M.S. CHALLENGER. 



corona with the coronal muscle and the deltoid muscle lying above it. The wide hollow 

 space of the coronal umbrella cavity is filled, for the most part, by the powerful buccal 

 stomach, whose oral margin extends to its opening. The quadrilocular funnel umbrella 

 cavity (which is sharply defined by the four palatine nodes (gk) from the simple umbrella 

 coronal cavity) shows however an essential variation in our species. Whilst in Periphijlla 

 mirahilis the four conical interradial umbrella funnels traverse the whole length of the 

 central and the basal stomach, and meet above in the central point of the umbrella cone, 

 in Pervph&ma regina they stop some little way below the cone; the four points of the 

 funnels are here inserted separately at four interradial points of the umbral wall of the 

 flattened basal stomach, which are at 4 cm. distance from each other. This occasions a 

 perfectly different formation of the basal stomach, which chiefly justifies the foundation 

 of the genus Periphema. 



Apart from the differentiated formation of the basal stomach, the gastrovascular 

 system of Periphema regina shows essentially the conditions already described in detail 

 in Peripkylla mirabilis. Only the special formation of single parts and their comparative 

 sizes show unimportant differentiations. Of the three chief sections of the axial principal 

 intestine, the buccal stomach is the largest, being 8 mm. high, whilst the height of the 

 central stomach and of the basal stomach only amounts to 5 cm. 



The buccal stomach or oesophagus (fig. 3) is extremely fleshy and thick walled. The 

 four quadrants of the oesophagus were found as four isolated fragments, still partially 

 connected with the pieces broken off from the central stomach, in the bottle containing the 

 incomplete remains of our species. One such quadrant is represented in natural size in 

 fig. 3. Each quadrant contains a complete buccal pouch {bb), and the enclosing half of 

 the oral column touching it (ee). From the beast having been torn during its capture, 

 the oesophagus was quartered through the interradial meridian planes. The reconstructed 

 form of the buccal stomach is on the whole that of a cube of 7 cm. to the side ; more 

 closely considered, it forms rather an octagonal prism with alternating broad and narrow 

 lateral surfaces ; the former are formed by the buccal pouches, the latter by the oral 

 columns. The oral columns (" columnar buccales," fig. 3, ac), are remarkably strong, and 

 supported by a powerful, fleshy, gelatinous swelling. The adradial wings of the oral 

 columns (" alee buccales," ad) appear extremely fleshy, and laid internally in strong 

 longitudinal folds, whilst their interradial middle plate is thinner, very much extended 

 and diminished in size, towards the oral margin. The wings project internally con- 

 siderably above the lateral parts of the buccal pouches, so that they are arched out 

 on both sides into spacious wing pouches. The buccal pouches (" bursse buccales," 

 bb), when inflated would be almost hemispheroidal : their wall is supported by a thin, 

 elastic but firm, gelatinous plate, which is broadened below and rounded obtusely 

 at the oral margin. The distal ends of the eight adradial wings therefore project 

 most below at the oral margin (am), without running out into barbous filaments as in 



