BIGELOW: MEDUSAE AND SIPHONOPHORAE. 421 



the early descriptions of Siphonophorae and Medusae. And so far as 

 it goes, Esehscholtz's figure (1829, taf, 12, fig. 7) agrees very well 

 with the specimens here listed, and those I have recorded earlier, 

 particularly in the outlines of the hydroecium, and in the relative 

 proportions of that organ, of the somatocyst and of the nectosac, in 

 the absence of basal teeth, and in the outlines of the inferior necto- 

 phore. Esehscholtz's statement (1829, p. 138), that there are "an 

 der Schwimmhohlseite zwei Kanten" points in the same direction, 

 suppression of the dorsal ridge being a very characteristic feature of 

 the species in question. But his description of the opposite side of the 

 nectophore as having three angles, is not clear. 



Questions of this sort are the despair of the student of pelagic 

 coelenterates ; but when the probability that identification of an old 

 name is correct, is as strong as in the present case, it should be used, 

 until some actual reason to the contrary is adduced. 



Whether the Diphyes described by Huxley (1859) as D. appendi- 

 culaia actually belongs here is certainly open to question, for though 

 his figures agree with it in general form, in the very characteristic 

 outline of the hydroecium, and of the inferior nectophore (particularly 

 its closed hydroecium), he represents and describes the dorsal ridge 

 of the superior nectophore as well developed, whereas in all specimens 

 of D. appe7idiculata recently studied it is suppressed, except at the 

 basal end. Time has proved Huxley's figures so accurate in general, 

 that it certainly is not safe to assume him in error in this instance. 

 This much, however, is sure — either he was dealing with D. appcndi- 

 culaia, being deceived as ^o the extent of the dorsal ridge, or with 

 some Diphyes which has never been seen since, and which differs from 

 B. appendicnlata only in that ridge, and in the origin of the left 

 lateral ridge at the apex, instead of slightly below it. 



Although D. appnidiculata is one of the commonest and most 

 M^idespread of siphonophores, and has often been described, the con- 

 fusion which still obtains in the name to be applied to it makes it 

 desirable to summarize its most diagnostic features here, though a 

 detailed account with figures, has been given elsewhere (Bigelow, 

 1911b), so that there may be no mistake as to what species is meant. 



The superior nectophore has no basal teeth. Its hydroecium reaches 

 upward to about ^ of the length of the nectosac, and is of a peculiar 

 and very characteristic conical outline; basally it extends equally far 

 below the level of the mouth of the nectosac ; and its basolateral 

 margins are oblique. The somatocyst is long. There are only three 

 ridges at the apex, two ventral, and the right-lateral. The left- 



