HYDROIDA II 



II 



creeping colonies of Lafoea gracillima, and a number of colonies which have later been identified as 

 Lafoea pygm&a should doubtless be referred to Lafoea gracillima. Bonne vie, (1899 p. 62) notes in 

 her table as to the hydrothecae that they have "slightly outward-curving margin"; this does not agree 

 with Hincks's expression "hydrothecse . . . cylindrical, elongate and narrow" or with his drawing of 

 the species. In my first report on the hydroids from "Michael Sars" (1903 the table) I recorded Lafoea 

 pygmcea from several localities, giving also a drawing of the coppinia of the species; subsequent revi- 

 sion of the material has shown me that the specimen indicated is, like most of the others, a typical, 

 creeping Lafoea gracillima, while some few colonies are creeping Lafoea dumosa. Lafoea pygm<ea must 



40 



200 m. 



. 6 oo m. 



.._ looo m. 



Fig. II. Localities of Lafoea gracillima forma typica and forma elegantula -f- in the northern Atlantic. 



In the hatched regions the literature denotes a common occurrence of the species. 

 (The dates from British seas are incomplete on account of a general confusion with Lafoea fruticosd). 



thus mainly be regarded as synonymous with Lafoea gracillima and Calycella syringa, and can accor- 

 a ingly no longer be counted as an independent species. 



Lafoea gracillima appears in two forms, affording parallels to those of the following species. 

 The finely built forma typica is quite cosmopolitan in its occurrence, and has been met with in all 

 seas from pole to pole. In arctic and as far as can be seen also antarctic waters, there has also 

 developed, in addition to forma typica, a more robust and closely built forma elegantula, the stalk of 

 which generally commences with a single loose winding, continuing then in a varying number of 

 close turns. Forma elegantula is, as mentioned, arctic, but may (text fig. II) also at times penetrate 

 into boreal waters. 



