6 4 



PENNATULIDA. 



As a matter of comparison I may note that Ven-ill's specimen is 456 m ' n long, the breadth in 

 the middle 2 mm , the length of the peduncle ioo ram , whilst Studer says that his <,species probably 

 reaches to a length of upwards of a metre; the single entire specimen, however, measured only 47o mm . 



Of the specimens before me Nr. 6, 7, and 10 are damaged, more or less of the upper part of 

 the calcareous axis having been denuded; the others look as if they were entire, but a more thorough 

 examination of the upper part of the rhachis makes it doubtful whether the original upper end of 

 the colony is preserved. With exception of the specimen Nr. 9, which I take to be abnormal, and 

 which will be more particularly mentioned hereafter, the rhachis ends in a solitary polyp which, 

 moreover, on its axial (dorsal) side carries a solitary and rather conspicuous large zooid (see PI. I, 

 fig. 13 z). It would be natural therefore to suppose these to be the terminal (i. e. the original) polyp 

 and a terminal zooid, such as we know to occur in young Pennatula-co\on\es. But so far as I 

 can see, only six calyx-teeth are found in this apparently terminal polyp, as in the other polyps, 

 the lateral ones; now we might, with some probability, expect eight calyx -teeth and a fully developed 

 calyx-edge in the real terminal polyp, but the calyx-edge does not appear to be developed on the 

 side towards the apparently terminal zooid which, however, is difficult to decide with perfect 



certainty, as the polyp in question is always strongly contracted, so that the calyx-teeth join each 

 other. At all events, the terminal zooid is placed close to the calyx-teeth of the end-polyp, whilst 

 in Pennatula, as is well known, it is placed below at the base of the calyx of the terminal polyp. 

 In other words, it is placed exactly where the one zooid would be found, if the apparent end-polyp 

 is a lateral polyp. I am most inclined to suppose therefore, that the terminal polyp is the upper- 

 most lateral polyp present, and the terminal zooid one of the two zooids of this polyp together 

 with an adjoining small part of the rhachis, so that the real upper termination of the colony is close 

 to this zooid. But such a termination of the rhachis can scarcely be the original one; it is probable 

 that in all these specimens an upper part of the colony has dropped off either as a consequence 

 of earlier mutilation or perhaps through atrophy in a somewhat similar way as in the Virgularise. 

 That at all events, the original features are not found at the upper end of the longest specimen but 

 one (Nr. 2), although this end looks as in the others, may be concluded with certainty from the fact 

 that the calcareous axis ends immediately at the terminal zooid, cut off quite abruptly, and is there 

 of the same thickness as farther down. With regard to the others I have not been able -- even by 

 clearing (in oil of cloves and the like) to get a clear notion of the upper end of the calcareous axis, 

 but it seems to be tapering, and does not appear to be broken. On the other hand, the lower end may 

 easily be observed; it is found in the outermost point of the peduncle, and forms here a curved hook. 



