1910.] 



FROM MEUGUI ARCUIPELAOO. 



819 



Considerable variation occurs also in the proximity of the hydro- 

 thecse of the same latei-al serie,s, for while a marked gap sepaiates 

 some — usually on the distal portions of biunches — in many cases 

 the upper portion of one hydrotheca is pressed against the base of 

 the next (c/. PI. LXXVII. figs. 12 a, 12 b). An abnormality in 

 the formation of the hydrothecse is worth noting. Occasionally, 

 probably after some accident to the branch, the hydrotheca) first 

 formed thereafter, while normal so far as the adnate portion is 

 concerned, have an exceptionally long portion free (0*77 nnu., as 

 contrasted with the average O'l mm.), this part being tubular, 

 recurved, and having a rather indefinite margin. Its successor 

 is less, though still abnormally large, and the diminution con- 

 tinues until the noiinal size is reached after five or six hydro- 

 theca-pairs (text-fig. 79). 



Text-fiff. 79, 



Abnoniial hytU'cthetsc of SeHularella qimdridens, X 20. 



The pinna*, each of which arises beneath a hydiotheca, are 

 regularly alternate, thi-ee hydi'othecpe being interposed between 

 two pinnae on the same side. In one case a branch, of second 

 degree, was observed to spring from the lumen of a hydrotheca. 



The structures of the soft parts of the species, to which I have 

 seen no reference, show points of interest. The coenosarc of the 

 stem is arranged in a varying number of longitudinal strands, 

 usually three or four, which are connected irregularly by anasto- 

 mosing canals, and wliich, with their connections, line the perisarc. 

 In the branches the structure is less complicated. Thei-e, two 

 lai'ge longitudinal coenosai'c tubes are to be distinguished, one 

 running along each side of the branch, and threading its way 



