20 THE MEDUSAE. 



other species of Charybdea in which the canals in adults are branched, the 

 satne structures in the young are simple, it is altogether probable that 

 this difference is due merely to the difference in the stages of develop- 

 ment of the two series. Nor does the very slight difference in the shape 

 of the pedalia which Mayer has described seem of much importance, since 

 he studied C. grandis on fresh, C. moseri on preserved, specimens. On the 

 other hand, a peculiar crescentic form appears characteristic of the phacellae 

 of both forms ; and since they so closely resemble each other in other 

 particulars, e. g., large size, form, and number of canals, I believe that they 

 represent but a single species. 



I have likewise been able to examine two specimens of a very large 

 Charybdea from the Society Islands, in the collection of the Museum of Com- 

 parative Zoology, which also appear to belong to C. grandis. They are both 

 about 170 mm. high and of the same general form, with short pedalia, and 

 with the rhopalar niches high above the bell-margin. The phacellae, though 

 not in very good condition, form rather crescentic areas, each containing 

 many filaments, and the velar canals are branched, but unfortunately it 

 was impossible to count them, owing to the contracted condition of the circu- 

 lar muscles of the velarium. 



If my view that these specimens and C. moseri both really belong to 

 C. grandis be correct, that species would extend from the Hawaiian Islands 

 on the north to the Paumotus on the south, and thus show in its distribution 

 a close parallel to C. rastonii. 



CORONATA. 



In considering this order we may adopt the classification into families 

 proposed by Vanhoffen (: 02"). This scheme, it is true, is based chiefly on a 

 single character, that is, number of sense organs and of tentacles, and may 

 therefore be regarded as somewhat artificial. But this criticism is less serious 

 in such a structurally homogeneous group as the Coronata than it would be 

 in most other orders of Medusae ; while, on the otlier hand, the scheme which 

 he has outlined is not only suggestive of the apparent relationships of the 

 various genera, but is also convenient in actual practice, besides readily 

 allowing of future additions. One such addition has already become neces- 

 sary, the formation of a new subfamily, Paraphyllininae (Maas, :03), to include 

 Paraphyllina (Maas, : 03) and the fossil genus Paraphyllites (Maas, : 06"), in 

 both of which the usual radial arrano^ement of the marginal organs is re- 



