1676 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus 704. Pohjpetta,^ n. geu. 



Definition. — M e d u s e 1 1 i d a with numerous (ten to twenty or more) articulate 

 feet. 



The genus Polypetta comprises those Medusettida in which the number of feet is 

 very large and not limited, usually twenty to thirty or more. The few specimens of 

 this genus that have been observed are rather difterent ; and it may be that only the 

 two first species described in the following lines are true Medusettida ; they.jjossess 

 the usual distinctly alveolate feet, and are derived from the similar Mediisetta or 

 Gazelletta simply by multiplication of the feet. The two other species, however 

 (figured in PI. 116, figs. 1, 2, as Porospathis), belong perhaps to another family of 

 Ph.^odaria (Castanellida?); their shell-structure is peculiar and their feet not distinctly 

 alveolate ; they may therefore represent a peculiar genus Porospathis (Haeckel, 

 Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, 1879, p. 5). 



1. Polypetta p)olynema, n. sp. 



Shell campauulate, thorny, aljont as long as broad, with sliglitly constricted mouth, similar to 

 that of Gazelletta orthonema (PL 120, fig. 10). Shell-wall hollow, with irregular polygonal alveoles. 

 Peristome with a corona of eighteen divergent, curved, cylindrical feet of unequal size ; six larger 

 primary on the margin of the shell, the other twelve secondary, between the former, somewliat 

 above the margins at different heights. The feet are two to three times as long as the shell, irregu- 

 larly curved and distinctly alveolate, without appendages. 



Dimensions. — Length of the shell 012, breadtli Oil. 



Hahitat. — Central Pacific, Station 266, surface. 



2. Polypetta alveolata, n. sp. 



Shell campauulate, thorny, about as long as broad, very similar to that of Medusetta craspcdota 

 (PL 120, fig. 4). Shell-wall hallow, with subregular hexagonal alveoles. Peristome prolonged into 

 a short funnel-shaped proboscis, twice as long as the similar velum of the latter. The velum is 

 surro\inded by a corona of eight larger and eight to twelve smaller feet ; the larger are about as 

 long as the shell, divergent, irregularly curved, thorny, and distinctly alveolate ; the smaller feet 

 are scattered above the latter and form an immediate transition to the small spines of the shell- 

 surface. 



Dimensions. — Length of the shell 0-08, breadth 0-09. 



Habitat. — South Pacific, Station 284, surface. 



1 Po?i/peHa = Diminutive of Polypus. 



