PROCEKEDINGS 
OF THE 
ROYAL PHYSICAL SOCIETY 
SESSION CXLII. 
I.—Note on the Type Specimens of Plumularia_catharina, 
Johnston, and its so-called ‘‘stemless variety.” By James 
- Ritchie, M.A., D.Sc., Royal Scottish Museum. 
(Read 25th November 1912. MS. received 25th November 1912.) 
In a recent note, Dr Billard! has raised a question as to the specific 
characters of Plumularia catharina, Johnston. To answer this query and 
fix the characters of the type specimens of the species is the object of 
the present note. 
While the general descriptions given by Johnston and succeeding 
authors are sufficient, the specific characters residing in the lateral 
nematophores have been neglected or wrongly described. Johnston 
himself mentions only that “between the cells there is a series of minute 
tubular or toothed cells.” There is no mention of lateral nematophores, 
and his Fig. 62, in the original paper? (repeated in his subsequent 
monograph *) shows no sign whatever of lateral nematophores. Yet 
Johnston quotes with approval an observation of F. W. L. Thomas, that 
the internode “which bears the cell has also a cellule at its base, and 
two lateral processes about the middle: to these processes are articulated 
two ‘trumpets,’ whose height is equal to the mouth of the cell.”* This, 
I take it, means that the lateral processes bear one “trumpet” 
(nematophore) each. Johnston’s successors, while approaching, still fall 
short of the truth. Landsborough first figures clearly one lateral nematophore 
' Billard, Arch. Zool. exp. et gén., 1912 (5), Tome ix., Notes et Revue, No. 3, p. lix. 
* Johnston, Mag. Nat. Hist., vol vi., 1833, pp. 497-499. 
8 Johnston, A History of British Zoophytes, Edinburgh, 1838, fig. 16, p. 148; and 
London, 1847, 2nd ed., fig. 17, p. 98. 
* Johnston, Hist. Brit. Zoophytes, 2nd ed., Supplement, p. 465. 
VOL. XIX. A 
