CARADOCIAN CYSTIDEA FROM GTRVAN, 381 



The clearest evidence that I have been able to obtain up to the present is that 

 afforded by the British Museum specimen of Dendrocystis Sedgwicki (El 6031). The 

 photograph reproduced as fig. 6 of PI. I. is the outcome of patient preparation by 

 various methods extending over a year and a half, and, though not conclusive by itself 

 alone, it shows, in the region corresponding to that occupied by the vent in D. scotica, 

 a few curiously elongate plates, which must have been modified for some special 

 purpose. 



§ 75. Appearances similar to those shown in Barrande's figures of Dendrocystis 

 from Zahorzan are also seen in his figures of Dendrocystis from Trubsko (pi, 27, 

 ff. 20, 22), and are confirmed by E16024 and E16102 in the British Museum (§ 102 ; 

 text-fig. 7). Whether the lobe on which they are be adbrachial or antibrachial 

 is uncertain ; but one infers that a vent existed at the proximal end of the theca 

 in D. Barrandei also. 



Whether Dr Jaekel had precisely these appearances in mind when he penned the 

 phrase "mit seitlichem After," is perhaps unimportant; but the reason for raising the 

 question will appear in the next section. 



§ 76. Other Thecal Openings. — There is not in Dendrocystis, any more than in 

 other Heterostelea, evidence for a hydropore of whatsoever kind, or for a gonopore. 

 (Anything in my previous writings contrary to this sentence is erroneous.) Prof. 

 Haeckel, however (1896, p. 56), has drawn attention to certain appearances in 

 Barrande's pi. 26, ff. 1, 6, 10, 18, pi. 27, ff. 2, 6, 19, 20, which he regards as "a 

 third large opening — ? gonopore" on the antanal lobe of the theca, close to the stem 

 attachment. The fact that Barrande himself (as in the explanation to pi. 27, f. 6) 

 warns us against placing too much reliance on these portions of his drawings, should 

 not, after our experience with the anal structures, cause us to reject Haeckel's hypothesis 

 without examination. 



§ 77. In Barrande's pi. 26, f. 1, there is a pronounced semicircular notch at the 

 lower antanal corner of the theca (the right hand of the figure). In pi. 27, f. 6, there 

 seems to be some structure in this position. There is also some trace of the notch in 

 pi. 26, if. 16 and 18. Turning to specimens in the British Museum, one finds that in 

 E1602L the right-hand lower corner ends in rather a sharp point, and immediately 

 above this the outline is excavate (PL L fig. 7). A similar appearance is more obscurely 

 seen in El 60 19. 



§ 78. One concludes then that there is some objective basis for the appearances, 

 though their interpretation is difficult. A somewhat similar semicircular notch in 

 Ceratocystis is interpreted by Prof Jaekel as an anus. When, therefore, that author 

 ascribes a lateral anus to Dendrocystis, it is possible that he is referring to the present 

 appearance and not to that which I have above regarded as the true anus. 



§ 79. In. D. Barrandei there is no such appearance on the antanal lobe. In 

 D. scotica, however, there is, as previously stated (§ 58), a tendency to a pointing of 

 this lobe and a strengthening of the point by one or more stouter plates. I am inclined 



