24 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



the lower part of the bell is not directly continuous, as in Charybdea, with 

 the corresponding furrow in the upper part of the bell that is, the afr 1 

 of Figs. 24-27 is not continuous with the afr of Figs. 22 and 23, as is seen 

 by both being shown in Fig. 24. The upper furrow (afr) is continued 

 only a short distance, however, below the starting point of the lower (afr'). 



The pedalia conform entirely to the description given those of 

 Charybdea, except that there are three attached to the bell margin in 

 each interradius instead of one, and that the blade of each pedalium is 

 much narrower. 



The sensory clubs also show exactly the same relation to the bell and 

 exactly the same structure. 



In the bell cavity the proboscis has a longer and better denned stalk 

 than that of Charybdea, and has the further and more important differ- 

 ence of possessing special sensory organs, to the number of fifteen or 

 twenty. The suspensoria are much more developed than in Charybdea, 

 so that the interradial funnels lying between are more marked. In a 

 corresponding way the frenula are larger and stouter (Figs. 28, 29, frn). 

 The musculature shows no new features and differs only in being com- 

 paratively more strongly developed and having a more pronounced 

 striation. The nerve ring follows the same looped course from the 

 margin in each interradius up to the level of the sensory clubs in the 

 perradius. 



c. Internal Anatomy. 



The stomach offers no peculiarities, and the phacelli also agree with 

 those of Charybdea except in having a smaller number of filaments in 

 each tuft. The stomach pockets are not guarded by such well-developed 

 valves as those described for Charybdea, though the valvular nature of 

 the lips of the gastric ostia is indicated and the valvular functions 

 undoubtedly performed. The gastric ostia are smaller (cf. Figs. 7 and 

 22), and this makes highly developed valves less necessary. No trace of 

 anything corresponding to mesogonial pockets was noticed. 



In the matter of the marginal pockets, however, we find that the 

 agreement with Charybdea is no longer continued. The regions that 

 correspond to the eight marginal pockets of Charybdea are formed, as in 

 that genus, by the coming together of the exumbrella and subumbrella 

 at the sensory niche (Figs. 25-28), but each of these regions is subdivided, 

 as it is not in Charybdea, into two marginal pockets, a larger (mp, Figs. 

 28-29) and a smaller (mp'). In this way sixteen marginal pockets are 



