ACTINIARIA 



and the papillae of Haloclava are to be regarded as slight stinging batteries (compare these genera!). 

 A ventral siphonoglyphe only occurs in Peachia, Haloclava, Eloactis, Pentactinia, Harenactis, Si- 

 phonactinopsis, Mesacmaea and Scytophorus; in the last genus it is rather slightly differentiated. The 

 other genera have either no siphonoglyphes or 2 not very distinct ones. A biradiate, hexamerous arrangement 

 of the mesenteries we find in Halcampoides, Acthelmis, Halcampella and Harenactis, though also here traces 

 of the bilateral development often appear, in as much as the 5th and 6th couples of the mesenteries of the 

 first cycle are weaker than the others of the same cycle. Scytophorus is furnished with 7 pairs of mesenteries 

 with apparently one pair of directive mesenteries, the ventral one. In Mesacmaea' which has not been ana- 

 tomically examined in details, 7 pairs of stronger mesenteries seem to be found, according to Andres's notes 

 which have been placed at my disposal. The ventral directive mesenteries belong to the stronger mesen- 

 teries, while the dorsal directives are weaker and in size like the mesenteries of the second order. In another 

 work I will give a more minute account of Andres's notes. Pentactinia has 10 pairs of mesenteries; the ven- 

 trolateral pairs of the second cycle are not developed. Peachia, Eloactis and Haloclava also have 10 pairs, 

 but here the dorsolateral mesenteries of the second cycle are absent. Finally Siphonactinopsis is furnished 

 with 20 pairs of mesenteries. Reproductive organs are developed on all mesenteries in Halcampoides, Scy- 

 tophorus, Siphonactinopsis, Mesacmaea (according to Andres's notes), Eloactis and Haloclava. Ciliated streaks 

 are present on all examined species. As to Harenactis Torrey (1902) has not given any minute inform- 

 ations concerning its filaments. InScytophomsthe ciliated streaks are discontinuous and found in several differ- 

 ent portions along the middle streak. According to Torrey cinclides 1 occur in Harenactis and according to 

 Annandale (1915) in Phytococtes. I have also found cinclides in Eloactis. Spirocysts seem to be absent in 

 the tentacles and oral disc of Eloactis and Haloclava. 



To this family also the genus Polyopis, proposed by R. Hertwig (1882), may probably belong. Unfor- 

 tunately a controlling of He rt wig's investigations of the already at the date of his investigation very deformed 

 specimen is no more possible, as there is not much left of the specimen now, and what remains has probably 

 once been exsiccated. Therefore I must restrict myself to some general reflections on Hertwig's descrip- 

 tion. Concerning the reduction of the tentacles his statement may be admitted with the greatest reserva- 

 tion. It is possible that the animal has thrown off its tentacles, another eventuality is that the tentacles 

 have been torn off or contracted so strongly that they project only as low walls. It was namely proved by 

 a control examination of Liponema (Me. Murrich 1893, Carlgren 1899) -- a genus devoid of tentacles, 

 according to Hertwig that the tentacles had been thrown off. R. Hertwig's statement that Sicyonis 

 has very short papilliform tentacles with large stomidia, is also incorrect. True enough, the tentacles of 

 Sicyonis are short, but they are not so reduced as Hertwig thinks, and the large stomidia are nothing 

 but artificial products due to the bad preservation of the tentacles, as I will afterwards prove. Finally we 

 might presume that the tentacles of Polyopis had been invaginated in the coelenteric cavity before the mace- 

 ration (comp. p. 79). I, for my part, do not think that the tentacles of Polyopis have been reduced, at any rate 

 not in such a way as described by Hertwig. Be this as it may, the rounded proximal body-end and the absence 



1 Stephenson (1920, p. 447) also names the apertures in the physa or proximal end cinclides. Though the walls, surround- 

 ing the cinclides and the apertures in the physa or proximal end, are of about the same structure, I think that it is most practical 

 to retain the name of cinclides in its original extent. 



Iti.- Ingotf-Expedition. V. 9. II 



