64 



MR JAMES RITCHIE : SUPPLEMENTARY REPORT ON 



Measurements :- 



Allman's specimens are somewhat more robust than those collected by the Scotia. 



Locality. — Dredged at the entrance to Saldanha Bay, Cape Colony, at a depth of 

 25 fathoms. 21st May 1904. 



The species has been recorded from Algoa Bay and Cape of Good Hope (Kirchen- 

 PAUER, 1884) ; South Africa (Busk, 1850) ; Simon's Bay, Cape of Good Hope (Allman, 

 1888). 



Plumularia curvata, Jaderholm, 1904 ( = i^- magellanica, Hartlaub, 1905). 



Dr Jaderholm has kindly drawn my attention to the fact that the species recorded in 

 my earlier report on the Scotia collections as P. magellaniccc, Hartlaub, had been pre- 

 viously described by him as P. curvata, which name I therefore substitute for Hart- 

 laub's synonym. A variation which does not seem to have been present in the examples 

 examined by Jaderholm or Hartlaub was described and figured in the earlier report 

 (pi. iii., figs. 1, la) ; here I wish simply to add that that variation is more general in the 

 hydroclades than I had at first supposed. My previous description reads: — "In the 

 proximal hydroclades .... tivo processes arise below and at the opposite sides of the 

 first hydrotheca, each of which bears a thecate internode, so that after the first hydro- 

 theca the hydroclade possesses two diverging branches each similar to the simple 

 distal hydroclades" (1907,*** p. 541). But this duplication of the hydroclade occurs 

 not only at the first hydrotheca but sometimes at successive hydrothecse as well. From 

 beneath the first hydrotheca two diverging internodes spring, each capped by its 

 hydrotheca ; from the bases of each of those second pairs arise, and from these again, 

 and so on in a system comparable to the false dichotomy of the Mistletoe, until 

 dichotomous pairs of even the fourth degree may be reached. Some of the hydroclades 

 thus assume a complicated and much-branched appearance, quite distinct from the simple 

 type figured by Jaderholm (1905, pi. 14, fig. 10) and Hartlaub (1905, p. 684, fig. N^). 



Measurements : — 



Stem internode, length 



,, ,, breadth 



Hydroclade internode, length . 

 Hydrotheca, depth 



,, diameter at mouth 



0-42-0-52 mm. 

 0-11-0-13 „ 

 0-24-0-2S ,, 



0-10 

 0-15-0-17 „ 



(roy. soc. edin. trans., vol. xlvii., 86.) 



