REPORT ON THE SIPHONOPHOR^. 83 



The collection of the Challenger contains different species of Velella, collected in 

 widely distant parts of the Atlantic and Pacific Oceans. The comparison of these species 

 and of others which I have seen in many museums, has led me to the opinion that about 

 a dozen different " good species," at least " geographical species," may be distinguished, 

 and that these may be placed in two different genera, Velella (sensu stricto) and 

 Armenista. 1 The genus Velella (sensu stricto), the type of which is the well-known 

 Velella spirans of the Mediterranean, has an elliptical umbrella with an integral, not 

 lobate margin, and a simple series of tentacles ; it stands nearer to the ancestral form 

 Rataria. 



The second, more differentiated nd larger genus, Armenista, has a more quadrangular 

 or parallelogram-shaped umbrella, with a broad lobate margin, and a double or multiple 

 series of tentacles. Perhaps even four genera may be distinguished when the numerous 

 local varieties are better known. 



The following species may be distinguished of the true Velella (sensu stricto) : — 



(1) Velella spirans, Eschscholtz, 1 (Mediterranean). 



(2) Velella caurina, Eschscholtz, 1 (North Atlantic, observed by me in 1866 



in the Canary Islands). 



(3) Velella scaphidia, Peron (12), collected by the Challenger in the Guinea 



Current (Stations 346 to 352). 



(4) Velella oblonga, Chamisso (21), collected by the Challenger off Volcano Islands, 



south of Japan (Stations 229 to 237). 



(5) Velella patella, Brandt (25), collected by the Challenger in the Tropical Pacific 



(Stations 265 to 279). 



Nearly related to the latter seem to be Velella pacifica of Eschscholtz and Velella 

 cyanea of Lesson (South Pacific). 



The other species of Velella described seem to belong to the following genus, 

 Armenista. 



Genus 9. Armenista? n. gen. 

 Velaria, Hkl., System der Siplionophoren, 1888, p. 31. 



Definition. — Velellidse, with a quadrangular or parallelogram-shaped (sometimes 

 sUghtly elliptical) umbrella, and a vertical triangular sail, placed obliquely in a diagonal 

 line of the parallelogram. Margin of the umbrella lobate. Pneumatocyst discoidal, of 

 the same form as the surrounding umbrella, with a vertical chitinous crest supporting 

 the sail. Submarginal corona of tentacles double or multiple. 



The genus Armenista (enumerated in my " System " as Velaria, a name already 



1 The name Velaria adopted in my System der Siphonophoren, 1888, p. 31, had previously been employed for a 

 Sponge (Aplysinidae). 



2 Armenista or Armenistarium (Carburiiis, 1757) is the Cephalonian term for sail= Velella. 



