ACTINIARIA 



Fig. 9. 



Fig. 10. 



Textfigs. 9 — II. Arrangement of tentacles and mesenteries in 

 Edivardsia andresi (fig. 9), E. claparedii (fig. 10) and Milne- 

 edwardsia loveni and carnea (fig. 11). In order to show the 

 arrangement in pairs, the imperfect mesenteries are drawn as 

 having pennons. In fact that is not the case. 



in Milne-edwardsia polaris. These clusters form weak 

 batteries of nematocysts. In the g^rnxsEdwardsia and 

 Isoedwardsia the nematocysts of the scapus are more 

 concentrated and enclosed in so-called nemathybo- 

 mes, forming strong batteries of stinging capsules. The 

 nemathybomes are now arranged in 8 longitudinal 

 rows as in E. titberculata, claparedii and longicornis, 

 now irregularly scattered as in E. vitrea, fmmarchica, 

 sipunculoides, intermedia and others. Possibly there 

 are more than 8 longitudinal rows in some species. 

 The nemathybomes appear the most distinctly in the 

 species with 8 rows. Here they are fewer in number, 

 but commonly larger and form conspicuous tubercles 

 on the scapus; on the other hand, if the nemathybomes are scattered they are smaller, but more 

 numerous and projecting a little or not at all over the surface of the scapus, according as the con- 

 traction of the animal is strong or weak. The nemathybomes form a capsule in the mesogloea and 

 are filled with more or less numerous nematocysts and their mother-cells. The walls of the nemathybomes 

 are formed by the mesogloea which is only perforated in the apex of the nemathybomes. Here the scapus- 

 ectoderm is in connection with the nemathybomes, and through the aperture the nematocysts eject their 



