86 BICELLARIIDJ3. 



The radical fibres are thin and membranaceous, and form 

 a dense and tangled mass at the base of the shoots. 



I have not been able to give many localities for D. 

 plumosa ; for the species was commonly confounded with 

 B. purpurotincta until Mr. Alder pointed out and defined 

 the differences between them, and it is difficult to decide 

 in many cases which of the two is intended. I have 

 recorded none about which there could be any doubt. 



BUOULA GRACILIS, Busk, var. UNCINATA, Hincks. 



Plate XV. figs. 1-4 ; Pate XII. figs. 6, 7. 

 J!i ana GRACILIS, Bunk, Quart. Journ. Micr. Sc. vi. 125, pi. xix. fig. 1. 



Zoarium composed of many slender shoots, about one inch 

 in height, united so as to form bushy tufts, of a pale 

 horn-colour when dry ; branches flabellate, somewhat 

 spirally disposed, crowded, dichotomously divided into 

 narrow segments, longest in the middle of the shoot 

 and diminishing above and below. Zocecia biserial and 

 alternate, elongate, narrowing slightly downwards, 

 with two spines on the outer side above, one of them on 

 the free angular extremity of the aperture, and one 

 (the longer) behind it, and one on the inner and upper 

 angle; aperture rather narrow, occupying two thirds 

 of the length of the cell or more, somewhat contracted 

 below, turned inwards towards the median line. Amcu- 

 laria small, placed on the outer margin, a little below 

 the top of the aperture. Uncinate prehensile appendages 

 distributed in considerable numbers over the dorsal 

 surface, and replacing the ordinary radical tubes. 

 Ooecia (?). 



HABITAT. Unknown. 



LOCALITIES. I am unable to give any British locality 



