NEAV ACTIXIANS FROM BRITISH COLUMBIA. 969 



The occurrence of P. quinquecapiiata in the same locality is nlso 

 suggestive, but the dift'erences between the two forms are too 

 marked to warrant their identification, although it is not im- 

 probable that these differences are due to age rather than specific 

 differences. 



The structure of Actinia davits of Quoy and Gaimard (1833), 

 recently studied by Pax (1912), shows, 1 believe, that it must be 

 considered congeneric with B. (pquoreon, although Pax refers it to 

 the genus Halcampa. As in the British Columbian species, there 

 are no indications of a conchuJa; but again, the form of the 

 siphonoglyph and the muscle pennons suggest PeacAm rather than 

 Salcampa, and until further evidence as to its exact position 

 is available, it would seem well that it should be known as 

 Bicidiu'm clavus.* 



The evidence as to the affinities of B. parasiticum is more 

 definite. It was first described by L. Agassiz (1859) from Cyanea 

 arctica and later by Yerrill (1864), who showed that it possessed 

 a well-marked trilobed conchula, and, still later (1866), assigned 

 it to the genus Peachia. Prepai-ations that I have of this species 

 show it to have a striking general similai-ity to B. wquoreoi, the 

 mesenteries being twelve in number, all perfect and all bearing 

 mesenterial filaments, and the siphonoglyph single and deep. 

 The muscle pennons also are of the same difftise type, but the 

 lamellse (fig. 8) are not arranged in the manner of a palisade, 

 but are decidedly branched in a dendritic manner so that 

 they present an appearance of being ai ranged in groups. It 

 is to be noted that Verrill (1874) mentions the capture of two 

 very large examples of this species, imbedded in gravel at low- 

 water mark at Eastport, Maine ; he does not, however, give any 

 anatomical data concerning them, and until it is definitely knoAvn 

 that the foi'ra develops the four pairs of secondary mesenteries 

 (zygocnemes), it seems advisable to allow it to remain in the 

 genus Bicidium. 



The form which F. Miiller (1860) described very completely as 

 Philomedusa vogtii is also undoubtedly a Bicidium. It occurred 

 upon the medusae Olindias and Chrysaora and was provided with 

 a trilobed conchula, twelve tentacles, twelve mesenteries, all of 

 which were perfect and furnished with mesenterial filaments, and 

 had a single siphonoglyph. The form described by Graeffe (1884) 



* The observations of Pax make it quite certain that R. Hertwi^ (1882) was in 

 error in identifying a Halcampa from the Kerguelen Islands with Quoy and 

 Gaimard's species. The possibility of Hertwig's forms being young examples of 

 Studer's JSdwardsia kerguelensis, which Kwietniewski (1896) has shown to be a 

 Halcampid, should not be lost sight of, although the differences in the descriptions 

 as they stand are too great to permit of a definite identification. Furtliermore, the 

 contention of Pax that the If. clavus of Tizard and Murray (1881) and Appellof 

 (1897) is distinct from that described by Hertwig is undoubtedly correct, but since 

 the forms so named by Appellof were the actual types of Danielssen's Ualcampoides 

 ahyssorum, it is difficult to understand the necessity for the new name, septeniri- 

 onalis, that Pax bestows upon them. 



