140 Scientific Proceedings, Royal Dublin Society. 



From the foregoing account it will be seen that four species 

 belonging to this family, and even to the genus from which it gets 

 its name, possess more than six pairs of perfect mesenteries. 



Heicler (Sitzungsb. d. k. Akad. d. W., Math. Nat., CI. lxxv., 

 Bd. i., Abth. 1887) describes and figures sections both through the 

 oral disk and through the oesophagus of S. troglodytes. He classifies 

 the mesenteries into seven orders, the first of which is composed of 

 twelve pairs, the second of twelve, the third of twenty-four, and so 

 on. In his description and figure of a section through the oeso- 

 phageal region, he makes the mesenteries of the first, second, and 

 third orders — forty-eight pairs in all — join the oesophagus. 

 Although he figures neither oesophageal grooves nor directive 

 mesenteries, yet it is certain that the section has passed through 

 the oesophagus, and not through the oral disk, as Professor Hert- 

 wig suggests, both from the presence of the oesophageal ridges, and 

 from the character of the epithelium. Further, in two small speci- 

 mens of this Actinia, obtained at South Devon, the arrangement of 

 the mesenteries was found to be as follows : — both possessed two pairs 

 of directive mesenteries ; in the smaller specimen, near the oral disk, 

 eight pairs of mesenteries reached the oesophagus; lower down, 

 however, the number was reduced to six pairs ; in the larger speci- 

 men, which was however considerably smaller than the average size 

 attained by this species, twelve pairs of mesenteries were perfect 

 throughout nearly the whole length of the oesophagus. It is cer- 

 tain, therefore, that the adult S. troglodytes possesses more than six 

 pairs of perfect mesenteries. 



Acontia are known to be present in S. troglodytes, S. miniata, 

 S. nivea, S. rosea, and S. venusta, so that in these five Actiniae we 

 have the presence of acontia unassociated with the special ar- 

 rangement of mesenteries, which Professor Hertwig claims for the 

 Sagartidce. 



Gosse's original genus Sagartia contained some species which 

 have been since removed from it ; but he himself (Actinologia 

 Britannica, p. 127) stated that if at any time the genus should be 

 broken up, he would retain the name Sagartia for the most typical 

 group which contains miniata, rosea, ornata, ichthyostoma, coccinea, 

 venusta, and nivea. Before Gosse had suggested this limitation of 

 the term, Milne-Edwards (1857, Histoire Naturelle des Coralliaires, 

 vol. i., p. 273) considered that Gosse had applied the name Sagartia 



