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



four feet simple, curved, with three edges, the posterior (caudal) foot larger, the anterior (sternal) 

 foot smaller than the two lateral (pectoral) feet. 



Dimensions. — Height of the sagittal ring 0-09, breadth 0'07. 



Habitat. — Tropical Atlantic, Station 351, surface. 



4. Stephaniscus medusinns, n. sp. 



Sagittal ring elliptical, thorny, with a larger apical horn. Basal ring nearly square, with short 

 marginal thorns and four large ovate gates of nearly equal size. All four feet of equal size 

 divergent, curved, irregularly branched, with short curved branches. 



Dimensions. — Height of the sagittal ring 013, breadth 0'09. 



Habitat. — South Atlantic, Station 332, depth 2200 fathoms. 



Genus 413. Semantiscus,^ n. gen. 



Definition. — S emantida with six typical basal feet (two sagittal, two pectoral, 

 and two tergal feet). 



The genus Semantiscus may be the archetype of those Nassellaria which exhibit 

 six typical basal feet, in combination with the sagittal ring. Three of these are the 

 primary feet of Cortina and Cortiniscus, the other three are secondary productions 

 between the former. The basal ring may possess either two, four, or six basal pores. 



1. Semantiscus hexajwdius, n. sp. (PI. 92, fig. 16). 



Sagittal ring elliptical, with a large branched apical horn. Basal ring small, square, with two 

 small triangular gates (or jugular pores). From its periphery there arise six short and stout 

 cylindrical feet, one very large (caudal) from the posterior corner, two tergal on each side, two 

 opposite (pectoral) from the lateral corners, and one odd sternal from the anterior corner. All six 

 spines bear a bunch of ten to twenty stout pointed conical branches, partly simple, partly forked. 



Dimensions. — Height of the sagittal ring 012, breadth 0'08. 



Habitat. — Central Pacific, Station 266, depth 2750 fathoms. 



2. Semantiscus hexaspyris, u. sp. (PL 92, fig. 18). 



Sagittal ring semicircular, broad, latticed, with two pairs of irregular dorsal and two pairs of 

 ventral pores. The dorsal rod is straight and vertical, prolonged upwards into a short serrate apical 

 horn, downwards hito a straight Hnear caudal foot. The ventral rod is curved and prolonged into a 

 similar sternal foot. Basal ring hexagonal, with four ovate gates (two smaller jugular and two 

 larger cardinal pores); its four lateral corners prolonged into four curved thorny lateral feet (two 



^ Semantiscus = Small signet-rmg; anfiauriaxo;. 



