RHIZOSTOMJB CATOSTYLUS. 



till.-, 



Among characters of minor importance, the marginal zone of circular muscles in the 

 subumbrella is only partially interrupted in the 8 principal radii. There is an exumbrella 

 pit with radiating furrows above each sense-club. 



VanhofFen, 1902, shows that Haeckel's Crambessa and Toxoclytus are identical and 

 must be merged. The only possible distinction appears to be that in Toxoclytus there are 4 

 separate genital sacs, whereas in Crambessa there is a unitary, cruciform genital cavity. 



Catostylus is very closely allied to I.\\ hnorhiza and Crambione, being distinguished solely 

 by having neither filaments nor clubs upon the mouth-arms. 



Haeckel's Crambessa is equivalent to the genera Catostylus, T'i\n>'l\tus, and Rhacopilus 

 of L. Agassiz, 1862. The name Catostylus takes precedence over all of the others, and 1 laeckel 

 should have used this name instead of inventing a new one. 



The lower ends of the mouth-arms of C. orsim and C. stiililniuiiiii are dc\oid of frilled 

 mouths and the extremity is blunt, triangular, and naked. 



Medusae of Catostylus are often found in brackish or muddy harbors. They are often 

 infested with commensal plant-cells which may give them a peculiar opaque yellow-brown 

 coloration as in C. mosaicus in certain parts of Australia; for von Lendenfeld finds that m the 

 harbor of Melbourne the medusa is not infested with plant-cells and is deep cobalt-blue in 

 color, whereas in the harbor of Sydney it is infested and is opaque, light yellow-brown. I have 

 also seen a swarm of these cobalt-blue medusa; in Brisbane Harbor, Queensland. 



It is possible, as Vanhoffcn surmises, that "Cephea" Jnht.-iiillii Reynaud (1830, Lesson's 

 Centurie Zoologique, p. 75, planche 23) may be a C<it'i\t\'lt<>. but the description and plate 

 are so unsatisfactory that I think knowledge will be advanced by dropping the species. It 

 comes from Pondichery, Indian Ocean. 



C.,iti>st\his is abundant in the Indo-Pacific region, but only 2 or 3 species are known 

 from the Atlantic coasts of Africa and southern Europe, and not one has been found in North 



Synopsis of the Forms of Catostylus. 



