Boone, Coelenterata, Cruises of "Ara" and "Alva" 43 



Material examined : A portion of the siphonophore with two 

 mature bracts attached and also the pneumatophore and a cor- 

 midium with the siphon, tentacles, several palpons, female and 

 male gonodendra. The bracts are each about 5.5 millimeters long. 

 The ''Alva" specimens were collected in 250 fathoms, about seven 

 miles off Fuerte Ventura, Puerto Cabras, Canary Islands, in the 

 Atlantic Ocean, February 18, 1932. 



Colour : In the living specimens the pneumatophore has pig- 

 ment spots of reddish purple, the stem opaque white or yellow, 

 the tentilla brilliant brick-red. 



Remarks : For full description of this species consult Dr. H. 

 B. Bigelow (1911, p. 281), whose analyses of an extensive series 

 of living specimens, obtained by the "Albatross" expedition to the 

 tropical eastern Pacific as well as West Indian material from other 

 sources have greatly augmented our knowledge of this remarkable 

 species, first described by Eschscholtz (1825) , and more fully de- 

 scribed and illustrated by Haeckel (1869, also 1888) , from collec- 

 tions from the North Atlantic area and from Ceylon. 



Agalma okeni is easily distinguished from its congeners by its 

 characteristic form and habit of floating horizontally in the water. 

 The largest colonies recorded range from 95 to 60 millimeters and 

 many much smaller. The stem is short, non-contractile, the bracts 

 are stiff, closely crowded in exceedingly precise and regular ar- 

 rangement, prismatic in outline and roughly triangular, thickest 

 at the distal end. 



References: Agalma okeni, Eschscholtz, Fr., Isis von Oken, 

 1825, vols. 16-17, p. 733-47, t. 5.— BiGELOW, H. B., Mem. Mus. 

 Comp. Zool., 1911, vol. XXXVIII, No. 2, The Siphonophorae, 

 p. 277, pi. 17 (extensive synonymy and full illustrations, also 

 analyses of large collection of living specimens) . 



Crystallodes rigida, Haeckel, E., Utrechter Gesell, Kunst.u.Wiss., 

 1869, p. 49, taf . 5, p. 65-71 ; Jena Zeit. Naturwiss. 1888, p. 40. 



