HYDRO MEDUSAE, SIPHONOPHORES, AND CTENOPHORES. 327 



Order NARCOMEDUSAE. 



In previous paper (1909a) I have discussed at length the struc- 

 ture and apparent relationships of the Narcomedusae and given my 

 reasons for adopting, in the main, the classification proposed by 

 Maas. Mayer (1910) has likewise accepted the main principle laid 

 down by Maas and me — namely, that the presence or absence of 

 gastric pockets is of prime importance ; the presence or absence of a 

 peripheral canal system of little significance in classification. 



A very different scheme has been outlined by Vanhoffen (1908). 



I have already (1909a, 1918) criticised his preliminary statement, 

 and Maas (1909) and Mayer (1910), with whom I entirely agree in 

 their general conclusions, have discussed his final account of the 

 Valdivia Narcomedusae. 



The only important difference between the scheme adopted by 

 Maas and by me on the one hand and the classification used by Mayer 

 en the other is that in the former Aeginidae and Cunanthidae are 

 distinct families; in the latter they are reduced to the rank of two 

 subfamilies of a single family. 



Family CUNANTHIDAE Haeckel, 1879. 



Genus SOLMISSUS Haeckel 1879. 



Sens. em. Maas (1904o-1904o).— Bigelow ( 1909a >.— Mater (1910). 

 Solmaris (part) Vanhoffen (1908). 



No part of Vanhoffen's classification of the Narcomedusae is fur- 

 ther from representing what I believe to be the natural relationships 

 of the forms involved than his treatment of Sohnissus. 



Vanhoffen's definition of his genus Solmaris is based upon the 

 statement (1908, p. 58) that " alle Solmariden auch mit Magentaschen 

 ausgestattet sind. Dass Magentaschen fehlen sollen, beruht auf 

 Beobachtung an jungen noch nicht genugend entwickelten Tieren 

 oder an mangelhaft erhaltenen Exemplaren." But we have the word 

 of Maas (1909, p. 34), of Mayer (1910), and of Neppi and Stiasny 

 (1913), that there are solmarids — that is, forms with neither otopor- 

 pae nor peripheral canals — which do lack any trace of true gastric 

 pockets when adult, the gastric margin running direct or on the arc 

 of a circle from tentacle base to tentacle base. And these students 

 made their observations not only on young or on fragmentary mate- 

 rial, but on living specimens in various stages of development, in- 

 cluding sexually mature adults. I can substantiate their statements 

 for an excellent adult specimen of Solmaris flavescens Kolliker from 

 the Mediterranean, a species recently redescribed by Mayer. The 

 margin of the stomach is entire ; there are no gelatinous septa in the 

 interradii. 



