1052 THE VOYAGE OF H.M.S. CHALLENGER. 



and sternal) larger, about half as long as the shell (shortened in the figure). The two sternal feet 

 larger than the two small or rudimentary tergal feet. 



Dimensions. — Shell 015 long, 013 broad ; feet 0-02 to 0-06 long. 



HaUtat. — Central Pacific, Station 271, depth 2425 fathoms. 



Subfamily 5. Pentaspyrida, Haeckel, 1881, Prodiomus, p. 442. 



Definition. — Zygospyrida pentapoda, with five descending basal feet, one odd 

 caudal foot, and two pairs of lateral feet (two anterior or pectoral, and two posterior or 

 tergal feet). 



Genus 456. Clathrospyris,^ Haeckel, 1881, Prodromus, p. 442. 

 Definition. — Z y g o s jj y r i d a with five basal feet and one apical horn. 



The genus Clathrospyris and the two following closely allied genera represent 

 together the small subfamily of Pentaspyrida, differing from the other Zygospyrida in 

 the possession of five descending feet on the basal face. Three of these are the primary 

 cortinar feet (of Cortiniscus, Plagoniscus, Tri'posjiyris, &c.), whilst the two others are 

 secondary tergal feet. The Pentaspyrida may therefore be probably derived from the 

 Hexaspyrida by loss of the odd anterior or sternal foot. 



1. Clathrospyris canielop>ardalis, n. sp. 



Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish. Basal 

 plate with six pores (?). Two pectoral feet very large, twice as long as the shell, cylindrical, 

 curved. Two tergal feet half as long and thick as the pectoral. Caudal foot and apical horn 

 straight, conical, half as long as the shell. 



Dimensions. — Shell 0'07 long, 0'09 Isroad ; horn and odd caudal foot 0'04 long ; pectoral feet 

 016, tergal O'OS long. 



HaUtat. — South Pacific, Station 297, depth 1775 fathoms. 



2. Clathrosjiiyris jyyramidalis, n. sp. (PL 95, fig. 9). 



Shell four-sided pyramidal, truncate, thorny, with slight sagittal stricture. Pores very large, 

 polygonal roundish. Two pairs of large pores on each side of the ring (at the frontal and the 

 occipital plate). Lateral pores more numerous. Basal plate with four large pores. The four 

 edges of the pyramid are prolonged into four short pyramidal divergent lateral feet (one-third as 



' Clathrospyris = Latticed ba,sket ; xT^iiS^oi', a-rrv^i;. 



