4 Proceedings of the Royal Physical Society. 
It has been generally admitted that this character of a pair of lateral 
sarcothecz on each side is of specific significance. Nutting (1900, p. 81) 
even regards it as of generic importance. Plumularia catharina has this 
character; but it is possible that the branched species so consistently 
described by authors as possessing only a single lateral sarcotheca on 
each side also exists, and is a species distinct from that of Johnston. 
In an endeavour to settle this question, I have examined specimens 
with the facies of Plwmularia catharina from the following localities, 
widely distributed off Scottish coasts:—Tiumpan Head, N.W.x W. 4 W. 
8 miles, 100 metres; Brora, W.N.W. 4 mile, 16 fathoms; Cromarty Zhclneme 
18 metres ; ane hendl S. x HE. 54 crib off Burghead and Lossiemouth 20-30 
fathoms; Lunna Holm, Shetland, N.W.5 miles; and “Goldseeker” stations, 
Nos. 7, 16, 41 and 56.1 Every specimen showed the characters of Johnston’s 
type. The probability, therefore, is that a species with solitary lateral 
sarcothece is exceedingly rare in British waters, if indeed such a species 
exists at all. 
Johnston and Hincks considered that there existed a “stemless 
variety” of Plumularia catharina, supposed by the latter to be 
Plumularia secundaria (Gmelin), and some later investigators have upheld 
this relationship of the two forms. The so-called “stemless variety,” 
however, is a distinct species. I have examined and recorded examples 
of it from the Mergui Archipelago, Burma; Interview Island, Andamans; 
Gulf of Manaar, Ceylon; and the Dogger Bank, North Sea. And in each 
case the specific characters agree with those of Antenella (Plumularia) 
secundaria, given by authors: the hydrotheca is flanked by a single 
supracalycine sarcotheca on each side, while above it, in the angle behind 
the hydrotheca, lies an insignificant unpaired median individual. 
The facts, therefore, that Plumularia catharina possesses a pair of 
lateral sarcothecze on each side, while Antenella secundaria has only 
one a side, and a single median individual above the hydrotheca, are 
sufficient to separate these species—apart altogether from their very 
different habit. 
On the other hand, an unsuspected resemblance is revealed between 
the minute characters of Pluwmularia catharina and those of Antenedla 
quadriaurita, Ritchie, obtained by the Scottish Antarctic Expedition from 
Gough Island, in the South Atlantic; for the latter, possessing the habit 
1 For permission to use these records of material collected by the Scottish branch of 
the North Sea International Investigation, I am indebted to Prof. D'Arcy W. Thompson, 
C.B. Figs, 2 and 3 are from a Lunna Holm specimen. 
