THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 89 



Locality. — A few colonies growing on the telson and under-parts of the body of 

 Palinostus lalandii (Lamk.) from Saldanha Bay, Cape Colony. 21st May 1904. 



Distribution. — Plumularia lagenifera, Allman, has been recorded from various locali- 

 ties off the coast of California by Marktanner-Turneretscher (1 890, p. 255), Nutting 

 (1900, p. 65), Torrey (1902, p. 77) ; from the neighbourhood of Vancouver Island by 

 Allman (1885, p. 157), Nutting (I.e.) ; and from the coast of Alaska by Torrey (I.e.). 

 The variety septifera has been recorded by Torrey only from Cataline Island, California. 

 The general distribution of the species and its variety is thus along the shores of the 

 Northern Pacific from California northwards to Alaska. That the present specimens 

 should have occurred on the eastern margin of the South Atlantic is indeed remarkable ; 

 but, in so mobile a group as the Hydroids, wide distribution is of little significance, and 

 the above record but adds another to the long list of species which spread beyond the 

 bounds of any one ocean. 



Plumularia setacea (Ellis, 1755). 



Specimens of an exceedingly minute and delicate variety of this species occur 

 creeping on gulf weed in company with Aglaophenia latecarinata. They are only 7 or 8 

 mm. high, and are unbranched, although in one case an appearance of bifurcation at the 

 base (a phenomenon recorded by Billard in this species (1907, p. 210)) was given by 

 a second colony being fixed to the first by its hydrorhiza. The hydroclade internodes, 

 both thecate and athecate, are long and slender and contain two distinct septa, a distal 

 and a proximal. While the rule is that a single athecate internode separates two thecate 

 internodes, very rarely two intermediate internodes occur, in which case one or the other 

 bears a single nematophore, the other lacking such an organ. Yet each of the internodes is 

 complete as regards the internal septa, containing one at each end. They are distinct inter- 

 nodes and seem to be due to spontaneous variation, for no hint could be observed that, as 

 Billard found in his specimens, rupture and subsequent regeneration had taken place. 



Our specimens appear to be similar to the " distinct variety " recorded by Professor 

 Nutting from gulf weed (1900, p. 57), although Nutting's specimens differ in being 

 branched. 



Detailed measurements indicate that the Scotia specimens stand intermediate to the 

 variety found by the Travailleur at Cape Spartel and to the south of Madeira, and the 

 typical form whose dimensions Billard records. 



Measurements : — 



Height of colony 



Length of stem internodes 



Breadth of ,, „ 



Length of intermediate internodes 



,, thecate internodes . 

 Breadth of ,, 



7-8 mm. 

 0-33-0-39 mm. 

 0-075-0-09 „ 

 0-14-0-21 „ 

 0-31-0-40 „ 

 0-42-0-48 ., 



Locality. — Creeping on gulf weed found in spawn net at Station 538. Lat. 32° 1 1' N. , 

 long. 34° 10' W. 30th June 1904. 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART I. (NO. 4). 12 



