Gr. T. and A. F. Dixon — On Bunodes thallia, etc. 323 



longitudinal muscles are turned in the same direction as those of 

 the perfect mesenteries adjoining. At this level we accordingly 

 find sixteen mesenteries which, in arrangement, conform to that 

 described by Blochmann and Hilger (1888, Morphologisches Jahr- 

 buch, 13 Band, 3 Heft), in Gonad in ia prolifera, Sars. 



Lower down two other pairs of small mesenteries appear. 

 These are developed in the exocceles nearest the last mentioned 

 small pairs of mesenteries. The arrangement at this stage cor- 

 responds to that found in the adult Peachia hastata, Gosse. ( Vide 

 Faurot, Comptes rendus, Tome xcviii., No. 12, 1884, p. 756.) 

 Finally, still lower down, two more pairs of mesenteries appear in 

 the remaining unoccupied exocceles, and so present to view twelve 

 pairs of mesenteries which correspond to the regular hexactinian 

 type, except that only eight mesenteries are perfect and reach the 

 oesophagus (PL v. fig. 4). It is to be noted that the sections which 

 exhibit these various phases of development are very close together, 

 and that the "secondary mesenteries " quickly become of equal size. 

 Thus, in a single young specimen of Bunodes verrucosa, by making 

 transverse sections at different levels, we obtain illustrations of 

 the permanent conditions met with in several different genera, 

 viz. : Edwardsia, Halcampa, Gonactinia and Peachia. We may add 

 that we have arrived at precisely the same results in similar in- 

 vestigations carried out in the case of young specimens of Actinia 

 mesembryanthemum and Cereus belt is. 



We think it may fairly be stated, as the result of these obser- 

 vations, that Bunodes thallia and T. bunodiformis, if not identical, 

 should at least be looked on as more closely allied to each other 

 than to either of the two other forms with which we have compared 

 them. 



Grosse included in his family Bunodidae all those species " the 

 surface of whose column is studded with persistent tubercles, and 

 which are not provided with marginal spherules, nor with perfora- 

 tions of the integument." He constituted Bunodes and Tealia the 

 typical and sub-typical genus of this family, the distinguishing 

 characteristics of these two genera being the possession of tubercles 

 (warts) arranged in vertical lines [Bunodes] , or irregularly scattered 

 ( Tealia) . Professor Hertwig found among the " Challenger " mate- 

 rial an Actinia which, according to Gosse's definition, he had to 

 refer to the genus Bunodes, but which had more in common, as he 



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