REPORT ON THE ANTIPATHARIA. 49 



transverse axis in other genera, and numbers 1-6 and 3-4, those situated at each extremity 

 < if the sagittal axis. It will be seen that the elongation of the stomodaeum for the greater 

 part of its extent is situated in a plane parallel with that of the sclerenchymatous basis, 

 and that each extremity is turned to the same side. The mesenteries numbered 3 and 4 

 are normally situated as regards the extremity of the stomodseum to which they are 

 attached, but are situated obliquely in the ccelenteron. Number 6 is, however, 

 displaced from its normal position, which is on the opposite side of the extremity of the 

 stomodaeum to that to which it is attached. In other words, there are four mesenteries 

 on one side and only two on the other. This fact is brought out more clearly in fig. 

 13, which represents the arrangement at a considerably lower level. It will be seen from 

 fig. 13 that the mesenteries in this region have a tendency to become arranged in groups 

 of three, which have a direction somewhat parallel with the horny axis. The mesenteries 

 numbered 6 and 3 are the only ones which retain their primitive position ; numbers 4 

 and 5 have been bent down so as to approach number 6, whilst numbers 1 and 2 have 

 taken up a position nearer to number 3. It will be noticed also that number 1 is now 

 situated much closer to number 2 than in the previous section, and that in consequence 

 the space between numbers 1 and 6 is considerably increased. This section of the 

 ccelenteron opens into the base of a tentacle, as also does that between numbers 3 and 4. 

 Fig. 14 represents a section close to the base of the stomodaeum. The stomodaeum 

 is here more complexly folded, but its greatest length almost corresponds with the 

 transverse axis — a feature which becomes more and more marked in passing from its 

 upper to its lower extremity. The mesenteries bordering the sagittal axis have now 

 almost reached the position which they usually occupy in other types. The transverse 

 mesenteries are continuous below, with the single mesentery of the gonozooid on each 

 side, which morphologically forms a portion of them. The mesenterial filaments are 

 ribbon-like bands of cells, occupying the base of the ccelentera, and are apparently most 

 prominent in the interzooidal areas and at the base of the gonozooids. Sometimes the 

 ccelenteron of a gonozooid is almost entirely filled with coils of these filaments, the 

 sexual elements being then situated chiefly at the upper extremity, close to the wall of 

 the peristome. 



In the specimen examined the gonozooids all bear seminal capsules, varying consider- 

 ably in number and size in different zooids. The testis appears as a specially differentiated 

 band of cells attached to the walls of the gonozooid by its margin, and is usually 

 separated from the mesenterial filaments in the greater portion of its surface. It has 

 similar relations to those of the ovary in Antipathes dichotoma. Judging from a com- 

 parison of a number of gonozooids, it appears that the mesenterial filaments become 

 reduced in bulk during active periods of spermatogenesis, so as to make room for the 

 i acreased size of the testis. 



(ZOOL. CHALL. EXP. PART LXXX.— 1889.) Llll 7 



