General History of the Marine Polyzoa. 145 
‘ Annals,’ March 1885 (p. 245). 
Diachoris quadricornuta, sp. n. 
Jullien’s species D. mawilla* has been referred to the 
resent form ; but in the absence of specimens of the former 
T should hesitate to identify them. 
.¢ 
Ibid. (p. 247). 
The footnote may be cancelled; I have already given my 
reasons for uniting Déachoris with "Beanta, 
‘Annals,’ March 1891 (p. 286). 
Flustra spinuligera, sp. 0. 
Though I have treated this form as distinct from Carbasea 
rhizophora of Ortmann, there may, I think, be a question 
whether it should not varie be regarded as a variety of the 
Japanese species. There is a remarkable similarity between 
them in most of the leading characters. 
The zocecia agree in all respects but one. In /. sprnuligera 
the margin bears a continuous line of short spines, and within 
the margin and just below it there is a line of minute denticles ; 
these are wanting in C. rhizophora. But the form of the 
cell, the orifice, the ocecium, and the avicularium are alike in 
both. When we come to the zoarial characters we meet with 
some dissimilarity. 
The South-African form is unilaminate and erect; the 
Japanese bilaminate and decumbent, and attached by tubular 
fibres springing from the dorsal surface. 
The marginal spines, as we know, are not very constant 
among the Polyzoa ; the internal denticles might very possibly 
escape observation. Both unilaminate and bilaminate forms 
occur within the limits of a species; so that the decumbent 
habit and the radical appendages would seem to be the most 
important distinctive characters. Taking into account the 
perfect agreement of the zocecia in all the most significant 
elements, we shall, I think, best represent the relationship 
between the two by ranking Plustra spinuligera as a form of 
Flustra rhizophora +. 
* ‘Cap Horn,’ 74, pl. vii. fig. 3, pl. xi. fig. 4. 
+ The genus Car ‘basea is founded on a very trivial zoarial character, 
and, in my judgment, should be abolished or restricted to such of the 
forms now included in it as may represent a distinct specific type. 
