HYDROIDA II 



has evidently on several occasions been confused with Halecium scutum. The same applies in part 

 to certain of the records from southern waters, where the species has undoubtedly often been mixed 

 up with Halecium Beanii. 



Halecium Beanii Johnston. 

 1847 Halecium Beanii, Johnston, A history of the British Zoophytes p. 59, pi. 9, figs. 1^2. 



Upright densely built colonies with polysiphonic, fairly robust main stem, and monosiphonic, 

 pinnately ramified outer branches; the ramification of the colony presents as a rule a main plane. The 



zoom. _ _ _____ 600 m. ......._._ looom. 2ooom. 



Fig. XII. The distribution of Halecium halecmum in the northern Atlantic. 

 In the hatched regions the literature denotes a common occurrence. 



minor branches are divided into slender regular internodia; the distally situate, hydrotheca-bearing 

 apophyse is almost of the same breadth as the branch itself, and sharply defined; the length of the 

 internodium is about 2 2.5 times the distal breadth (including apophyse). The hydrothecse small, 

 bounded on the lower side by a slight diaphragm. The primary hydrothecae are hardly more than 

 an aperture in the apophyse, and the hydranth is evidently very soon renewed ; the basal chamber of 

 the secondary hydrotheca is symmetrical, with a distinctly marked basal expansion; above this the 

 hydrotheca stalk is narrowest, its breadth increasing slightly from there until it passes over into the 

 somewhat obliquely set hydrotheca; the latter is a little broader at the aperture than at the diaphragm; 

 opening margin not outward curved. 



Gonothecse of medium size, proceeding from the apophyse of the primary hydrothecae. The 



