WEST COAST HYDEOIDS 55 



f 

 these 7 there has been little objection made. Hartlaub,-^ War- 

 ren,^" Billard^^ and Ritchie,^- who have made large contributions, 

 and others who have made smaller contributions, have used this 

 classification as it is, for these genera. Jaderholm^^ has included 

 Abietinaria with Diphasia, but otherwise has not departed from 

 the classification. In each of these the operculum consists of a 

 single adcauline flap, but the shape of the hydrothecae and the 

 mode of gro\^-th are different. In species of Diphasia, where the 

 gonosome has been found, it is widely different from that which 

 is found in species of Abietinaria. 



Broch and Torrey are the only notable exceptions whose pa- 

 pers I have seen. Broch^* has cut do^^Ti the 7 genera to 5. but 

 has introduced a number of sub-genera, so that the main di- 

 A-isions are more numerous than in Nutting's classification. Very 

 little can be gained by combining Diphasia and Abietinaria into 

 the one genus Diphasia, and then dividing the genus into the sub- 

 genera. Diphasia and Abietinaria. It would seem to be more 

 satisfactory to combine them and leave them that way, as Jiider- 

 holm has done, than to separate them thus. His treatment of 

 Selaginopsis is rather unfortunate, when two forms that have as 

 much resemblance to each other as S. mirabilis and S. obsoleta, 

 are put in two genera, while at the same time, such unlike forms 

 as 8. mirabilis and Sertularia piDnila are placed in the same 

 genus. He has placed much emphasis on the trophosome as far 

 as its individual components go, and none whatever on the gen- 

 eral appearance, mode of g^o^vth and the features of the gono- 

 some. 



Torrey prefers to follow the grouping method of Schneider,^^ 

 but no other systematist since his last paper appeared, seems to 

 take this method of classification into serious account. He gives 



29 Die Hydroiden der Magalhaenischen Kegion. 190.5. 



30 On a Collection of Hydroids mostly from the Xatal Coast, 190S. 



31 Hydroides du " Travailleur " et du "Talisman", 1907 and Hydroides 

 du British Museum, 1910. 



32 Hydroids of the Scottish Antarctic Expedition, 1907 and its Supple- 

 ment, 1909. 



33 Xorthern and Arctic Invertebrata in the Swedish Museum, Sect. r\', 

 Hydroiden, 1909. 



34 Die Hydroiden der Arktischen Meere. 1909. 



35 Hydropolypen from Eovigno, 1S97. 



