288 THE SCOTTISH NATURALIST 



(see Scot. Nat., 1913, p. 142), and may now be regarded as a well- 

 established Scottish species. — James J. F. X. King, Glasgow. 



Curious association between a rare British Polyzoon 

 (Triticella pedicellata) and the Hydroid, Dicoryne conferta. 



— During the examination of a collection of Hydroids made by the 

 Scottish Committee for the Investigation of the North Sea, specimens 

 of the graceful Polyzoon, Triticella pedicellata (Alder), were noticed 

 on an empty and badly damaged shell of Neptimea. The shell was 

 dredged by the Goldseeker in lat. 57° 43' N-, long. 0° 38' E., 

 some 100 miles east of the northern portion of the Aberdeenshire 

 coast. The polyzoon species was originally obtained off the coast 

 of Northumberland in 1857 and in 191 2, as a record from the Firth 

 of Clyde (in Prof. L. A. L. King's "Supplementary List, Clyde 

 Marine Fauna "), was definitely added to the Scottish fauna. In 

 1903-4, however, the Michael Sars, during the investigation of 

 the North Sea, obtained several shells bearing Triticella pedicellata 

 from two stations some distance off the east coast of Scotland 

 (H. Broch, in Bergeu's Museum Aarbog, 1905, No. 6, p. 7). It is 

 remarkable that this rare Polyzoon should be almost invariably 

 associated with a particular hydroid, Dicoryne cofifcrta. The shell 

 dredged by the Goldseeker in the North Sea bore a thick coating 

 oi Dicoryne ; the Clyde specimens are accompanied by Dicoryne or 

 Perigonimus. Broch found Dicoryne conferta from the west coast of 

 Norway to the west of Denmark, and in the central portions of the 

 North Sea, " very frequently along with a small Bryozoa, Triticella 

 pedicellata'^ (J.oc. cit.) ; and Hartlaub records that amongst the polyps 

 of Dicofyne conferta found in the neighbourhood of Heligoland the 

 same Polyzoon is regularly present (Hartlaub, in IViss. Meeresunters., 

 N.F., Bd. I, 1S94, p. 167). There are indeed few records of 

 Triticella pedicellata where Dicoryfie conferta is not also mentioned, 

 and the constancy of the association almost suggests a form of 

 commensalism. — James Ritchie. 



