ACTINIARIA 



weak pennons and is devoid of filaments and reproductive organs. The 6th couple, the ventral mesenteries 

 of the ventro-lateral pair, is only a little stronger than the subsequent mesenteries, which are all sterile and 

 devoid of pennons and filaments. No distinct parietal muscles are present. The parieto-basilar muscles 

 one half of the parietal muscles hardly show any folds, not even on the perfect mesenteries. Basilar muscles 

 are absent. There are ciliated streaks. I cannot, however, describe their appearance as they have been hit 

 longitudinally. Typical acontia with close, large nematocysts are present, but I cannot decide which mesen- 

 teries have acontia. They have not been observed by Fowler. I think that the genus Octineon may be cha- 

 racterized as follows: 



Andwakiidae with very wide basal disc and low conical body, much smaller in the distal part than 

 in the proximal one. Column divisible into two regions, a proximal part, scapus, the lower part of which 

 forms the flattened basal disc, and a short distal part, capitulum. The ectoderm of the scapus with a cuticle 

 and "Halcampa-papillae" (to which grains of sand are attached). Capitulum without a cuticle and spiro- 

 cysts. Sphincter mesogloeal, very elongated. Tentacles 12. No distinct siphonoglyphes. The 8 "Edwardsia- 

 mesenteries" (or some more mesenteries?) perfect, fertile, with filaments and strong, perfectly circumscript, 

 pinnate muscle-pennons. The 5th couple with weak pennons, but without filaments and reproductive organs. 

 The 6th couple and the subsequent mesenteries like the 5th couple, but weaker and without pennons. Nu- 

 merous mesenteries in the proximal part of the body. Parietal muscles not distinctly differentiated, weak 

 parieto-basilar muscles. Ciliated streaks and acontia present. 



Octineon is particularly interesting because of the transformation of its proximal body-end. Instead 

 of forming a physa this part is flattened like a regular pedal disc (compare Milne-edwardsia carnea 

 (p. 16,63) which, under certain circumstances, can flatten its proximal part) and, in comparison with the distal 

 part, considerably increased in size and provided with "///caw^a-papillae", to which grains of sand are 

 attached. Thus the proximal body-end serves as a good anchor to the animal which is incapable of attaching 

 in the usual way. 



Genus Andwakia Dan. 



Diagnosis: Elongated Andwakiidae with the column divisible into physa, scapus and capitulum, 

 the first of which being only a little differentiated from the second. Scapus with "//a/caw^a-papillae". Capi- 

 tulum without spirocysts. Sphincter elongated, strongly mesogloeal in the distal part reaching the basal 

 region of the tentacles as in Halcampa. Tentacles more than 12. Two rather feebly developed siphonoglyphes. 

 6 pairs of perfect and fertile mesenteries with strong muscle-pennons. One or several cycles of sterile(?) im- 

 perfect mesenteries with weak muscles without pennons. Acontia present, but few in number. Column with 

 cinclides(P). 



The above diagnosis of the genus only slightly agrees with that given by Danielssen 1890. Also 

 my description of the species differs considerably from that of this author. As it would be too elaborate to 

 point out all the differences between my conception of the organisation of Andwakia mirabilis and that of 

 Danielssen, I here give a mainly new description of the species which nowise deserves the name of mira- 

 bilis. On the contrary its organisation scarcely deviates from that of a typical Actinia, as far as I can see. 



