194 ROBERT PAYNE BIGELOW ON 



SYSTEMATIC PART. 



Genus Cassiopea PERON and LESUEUR (1809). This genus, as limited by 

 Haeckel ('80) , may be defined as follows : Discomedusae without tentacles and without a 

 central mouth opening ; provided ? instead of the latter, with numerous oral funnels at- 

 tached to the ventral, or axial, side of the eight oral arms, which are pinnately or tricho- 

 tomously branched, have a subcylindrical, or subconical, gelatinous support continuous 

 to the tips of the principal branches, are provided with numerous chtb-shajjed vesicles 

 among the oral funnels, and are without appendages on the dorsal, or abaxial, side ; 

 also with four interradial gonads in the aboral wall of the four separate subgenital cav- 

 ities; sixteen marginal sense organs (rhopalia); and thirty-two radial canals connected 

 by a network of anastomosing branches. 



For the sake of clearness this definition is made to include the characters of the 

 family Toreumidae Haeckel, to which this genus belongs, and the purely generic charac- 

 ters are italicized. 



Cassiopea xaxnachana. 1 



Cassiopea xamachana BIGELOW, Zool. Anzeiger, no. 393, 1892, pp. 212-214. 



(?) C.frondosa FEWKES, Bull. mus. comp. zool., vol. 9, no. 7, 1882, pp. 254-259. 



Diagnosis. A Cassiopea with a disc-like umbrella, concave on the aboral side ; 

 when regular, with eighty short and obtuse marginal lobes separated by deep grooves on 

 the surface of the exumbrella (in each of the sixteen parameres three velar lobes between 

 two ocular ones) ; white markings on the exumbrella, consisting of a circular band with 

 a diameter somewhat greater than that of the concavity, within this sixteen oval or elip- 

 tical spots lying in the radii of the rhopalia, and on the outer side eighty marginal spots, 

 one for each marginal lobe ; oral arms rounded and slender, never angular, exceeding the 

 radius of the umbrella by at least one half of its length, and bearing nine to fifteen 

 primary branches which are, in turn, copiously branched, giving the whole appendage a 

 spatulate outline ; very numerous small oval vesicles attached at the axils of the small 

 branches and thickly massed upon the oral disc of adult females, and many small and a 

 few large, flattened, linear vesicles attached one at the axil of each of the larger branches 



1 This name, suggested by Professor Brooks, must stand as printed in the preliminary description of the species, 

 according to the current rules of nomenclature, followed by the Boston Society of Natural History. But it should have 

 been written xamaycana, from Xamayca (the x is pronounced like ch in the German ach), the Indian name for the island of 

 Jamaica, as written by the early Spanish historians (see Herrera, Novi orbis pars duodecima, sive descriptio Indiee occiden- 

 talis, 1024 ; also Encycl. Brit., 9th ed., article, Jamaica). The form Xaymaca given by Bridges, Annals of Jamaica, 1827, 

 and followed by several subsequent authors, is probably a misprint. 



