PEGANTHA MARTAGON. 83 



to Polyxenia; while of four specimens of P. laevis two would fall in 

 Polyxenia, and two would be intermediate between that genus and 

 Polycolpa. For this reason it seems better to neglect this character 

 entirely as the basis of generic diagnosis, and to follow Haeckel in including 

 in Pegantha all species in which the gonads are restricted to the marginal 

 region of the gastric wall, and localized in interradial pouches. 



Pegantha Haeckel, 1879. 



Solmaridae with canal system and otoporpae ; the gonads forming diver- 

 ticula of the margin of the oral gastric wall. 8-32 tentacles. 



This genus, since first described by Haeckel (79), has been recorded by 

 Fewkes ('89*) from the Gulf Stream ; Maas ('93) from the Tropical Atlantic ; 

 Bigelow (: 04) from the Indian Ocean ; and by Mayer (: 06), under the name 

 Solmaris hisculpta, from the Hawaiian Islands. It is now well known ana- 

 tomically from the studies of Maas and Haeckel, but up to the present time 

 no early stages in its development have been observed. Therefore I am 

 fortunate in being able to trace in detail in a new species, P. smaragdina, 

 a form of parasitic development from the egg, very closely resembling that 

 known to occur in Cunina proboscidea (Metschnikoff'SG", Stchelkanowzew : 06), 

 and in demonstrating the occurrence of internal budding in a second species, 

 P. laevis. 



The distinctions between the various described species of the genus, as is 

 so often the case with oceanic Medusae, are by no means clear. The diffi- 

 culty is caused chiefly by the unsatisfactory nature of Haeckel's original 

 descriptions, and by the fact that he based his A^arious species chiefly on 

 differences in the conformation of the gonads, a feature which may change 

 with growth. 



The present collection contains four easily distinguishable species. Two 

 of these can be referred to P. martagon Haeckel and to P. triloba Haeckel. The 

 other two differ so markedly from any species as yet known that they are 

 described as new. 



Pegantha martagon Haeckel. 



Pegantha martagon Haeckel, '79, p. 332. 



Pegantha simplex Bigelow, : 04, p. 260, pi. 5, figs. 19, 20. 



Plate 18, Figs. 1-8. 

 Station 4634 ; 300 fathoms to surface ; 1 large specimen ; good condition. 

 Station 4637 ; 300 fathoms to surface ; 1 large specimen ; good condition. 



