The Actiuiae of tlie Plate Collectiou. 225 



tliaii tliey were in tlie more distal section. The peiiiions of the pri- 

 maries liave, however, almost disappearecl, except in the cases of 

 two mesenteries beloDging to different pairs, situated on the same 

 side of the sagittal plane of the bodj'. It seems certain that this 

 condition is partly dne to differences in the contraction of the mes- 

 enteries, but not entirely so. Heetwig (1882) has described a diifer- 

 ence in the size of the mesenteries of H. clavus whicli agrees with 

 the probable sequence of their development, and Faurot (1895) has 

 shown the same for adnlt specimens of H. cJirysantheUum (a form 

 comparable to the present species on acconnt of its possession of 

 twelve pairs of mesenteries). A section of the present species taken 

 at about the middle of the cohimn shows that the same correspond- 

 ence of size and sequence of development occiirs here also. Such 

 a section is shown in Fig-. 5 in which one pair of directives, B', has 

 practically lost the pennons, while they are still present, thoug-h 

 reduced in size on the other pair; furthermore, one mesentery of 

 each of the lateral pairs has lost its pennon. If we regard the 

 directives D as the third couple of mesenteries, these it will be the 

 fourth, fifth and sixth couples which have lost their pennons, a con- 

 dition corresponding with what occurs in H. ckrysantJwllum. 



Finally, it may be added that in sections through the proximal 

 (aboral) third of the column all the mesenteries have lost their pen- 

 nons except those of the first and second couples (Fig\ 5). The diffe- 

 rence seen on the two sides of this figure is also noticeable in Fig. 4 

 and is probably due to the section being cut soraewhat obliquel3\ 

 owing to the curvature of the column (Fig*. 1). 



I could not discover any mesenterial stomata, and the State of 

 preservation of the specimen was not favourable for an accurate 

 study of the filaments, though it may be stated that they were dis- 

 tinctly trilobed in their upper part and simple below, as in the ma- 

 jority of the Actiniaria. No acontia were present. The specimen 

 was a male, the reproductive organs occuring- on all the perfect me- 

 senteries, including the directives. 



H. cJiilensis presents many similarities to H. l-ergitelensis (Studee) 

 and the temptation to regard the two as identical is very great. 

 Until, however, opportunity is afforded for the proper study of the 

 sphincter of cliüensis it seems less conducive to a possible confusion 

 to regard them as distinct. 



