I 



I irdle divides two similar parts which are spherical in outline 



and are ornamented with symmetrically disposed verrucae. Such an 



arrangemi in the spicule which we will call the. Doublé Head. 



i .•• similar parts which are spherical in outline 



ïented with radiating points. These are Doublé Stars. 



I rod-like in genera! form, with a girdle dividing two 

 .-. hii'h are gradually enlarged toward the outer ends, have 

 nparatively straight sides, rounded distal corners and are covered 

 with fine and densel) aggregated verrucae. ["hese will be called . Doublé 1'. ars. 

 spicule is rod-like, without the girdle Bars. 



I 'ns\ mmetrical tornis. 

 I lx- girdle separates two unlike parts, one a club and the other a 



ir. Such forms may be called Club-Stars. 



6. The girdle separates two unlike parts. one a club and the other 



a head. Forms of this kind may be called Club-Heads. 



rhe girdle separates two unlike parts, one a star and the other a 



head. These will be called Star-Heads. 



d. The girdle separates two unlike parts, one a club and the other a 



spindle. This rather rare form may be called Club-Spindle. 



I irdle separates two unlike parts. one a star and the other a 

 spindle. ["hese may be designed as Star-Spindles. 



Besides the above, which may be called girdled forms, there are often crosses produced 

 by a doublé head being longitudinally divided by an impressed vertical zone. 



While it is true that a given species, or even a single specimen, may show several of 



these forms and numerous intergradations, it is also truc that certain forms predominate in a 



given genus, and it is these dominant types of spicules, and not the others, that are available 



ric diagnosis '. 



While the spicules are the most important features for generic distinctions, we may also 



avail ourselves of any other character which seems to be possessed by a group of allied 



t. mode of branching, shape of calyces, character of axis, etc, in attacking the 



problem before us. 



Artifical key to the genera of the Gorgonellid.*. 



Main branches arising from a forking of the main stem. Colony Babellate, 

 widely diverging, the main branches bearing a series of simple branchlets 

 on upper side only. Branchlets vertical and parallel, and resembling the 

 teeth of a comb Ctenocella 



!1 as a statement of tin- position of the author on the matter of the retention of estaulishcil 

 in the Report on the Muriceida uf the Siboga Expcdition, Ni i 1 1 s. . . 1910, p. 5. 



