l6 ACTINIARIA 



base, without a distinct disc (Verrill 1864)", "Actinianae liberae basi musculari carentes" (Andres 



1880), "Korper verlangert wurm- oder saulenformig, hinten zugespitzt, nicht scheibenartig verbreitet und 

 daher nicht festheftend, nur in Sand vergraben" (Klunzinger 1877), "Hexactinien mit abgerundetem 

 aboralen Korperende ohne Fussscheibe" (R. Hertwig 1882). Thus the absence of a real pedal disc is the 

 main character which these authors have given the Actinines pivotantes or Ilyanthidae, the same character 

 which distinguishes the Athenaria, still with the difference that the absence of the basilar muscles is 

 the principal character, while the shape of the proximal body-end, if pointed, rounded or flattened 

 disc-shaped, is of little importance as pointed out by me (1905 p. 517), though it is true that most Athenaria 

 commonly show a rounded-proximal body-end. This part is namely in certain species able to alter its shape, 

 f. inst. Milne-Edwardsia loveni alters the shape of its proximal end in accordance with the variation of the 

 canals in the dead Lophohelia-stocks, and the commonly rounded or a little flattened proximal end of Milne- 

 Edwardsia carnea is capable of flattening out disc-like, so that it gets a considerable breadth, at the same 

 time as the body becomes low and conical what I have observed in a specimen, the cuticle of which was 

 dropped in the aquarium (Compare Milne-edwardsia carnea). Halianthella (= Marsupifer) has the same 

 capability. A specimen of this latter, taken by the German deep-sea expedition was namely almost cake- 

 like and reminded of a very contracted Thenaria with a real pedal disc (with basilar muscles). The aboral, 

 flattened end was attached to a stone. Under such circumstances there is nothing at all to prevent referring 

 to the Athenaria such a genus as Octineon which is devoid of basilar muscles, and the proximal body-end 

 of which forms a wide, basal plate incrusted with sand. 



The absence of basilar muscles is common to the Athenaria, Protactininae and Protostichodactylinae 

 (Corallimorphidae, Discosomidae, Carlgren 1900). 



My suggestion to divide the Actininae into two groups, Athenaria and Thenaria, has been opposed 

 by Me. Murrich and Poche. Me. Murrich (1904 p. 221) declares that this division in Athenaria and The- 

 naria "tends to the confusion of unrelated forms and the separation of others which are nearly related", 

 an idea which I showed (1905 p. 517) to have no foundation whatever, in as much as I pointed out that the 

 opinion of Me. Murrich that the basilar muscles of the Thenaria are homologous with the parietal muscles 

 of the Athenaria, on which he mainly supports his statement, is false. At the same time I reject the supposi- 

 tion of Me. Murrich that Haloclava and Eloactis would be Thenarians. Me. Murrich prefers to divide the 

 Actiniaria at once in families "recognizing in addition to the Edwardsiidae, which will include in addition 

 to the Edwardsiae and Halcampidae (Auct.) the genus Scytophorus, the Gonactiniidae, which will include 

 Gonactinia, Protanthea and possibly Oractis, the Peachiidae, including Peachia and Haloclava and the Ilyan- 

 thidae having essentially the limitations recognised by Andres (1883)." On further examination we find, 

 however, that the enumerated forms are devoid of basilar muscles, while all other genera, described in the 

 paper of Me. Murrich 1904, are Thenarians. In the system of Pax (1914), which is for a great part 

 based on my works, he begins by placing among Nynantheae the same families as I myself (1900 p. 24), and 

 gives as first character "ohne Fussscheibe und Basilarmuskeln", while he continues by enumerating families 

 which are mainly characterised by the presence of a well-developed pedal disc, (an exception being made 

 by the free-swimming Minyadidae which belongs to the Stichodactylinae, owing to my examination (1914). 



