864 ^ THE VOYAGE OF H.M.S. CHALLENGER. 



as long as the radius of the sliell ; ii-raJually tapering from its surface towards both ends. By-spines 

 very short and numerous, simple. 



Dimensions. — Length of the shell 013, breadth O'll ; length of the spines O'DS, basal breadth 

 0025. 



Habitat. — Central Pacific, Station 271, surface. 



4. Belonaspis lanceolata, n. sp. 



Parmal pores elliptical, si.x or eight times as large as the small circular sutural pores. Each 

 plate surrounded by ten to twelve sutural pores (two on each side). Spines lanceolate. Hat, in the 

 distal part needle-shaped, about as long as the diameter of the shell. By-.spines very numerous, 

 zicfzag, half as long as the shell-radius. 



Dimensions. — Length of the shell 0-1.5, breadth O'lS ; length of the spines 0-14, basal breadth 

 0-03 ; length of the by-spines 004 



Habitat. — North Pacific, Station 235, surface. 



5. Bdonaspis conifcra, n. sp. 



Parmal pores kidney-shaped, three or four times as large as the small circular pores. Each 

 plate surrounded by ten to twelve sutural pores (two on each side). Spines very thick, half 

 as long in the outer conical part as in the inner cylindrical part. By-spines very short, conical. 



Dimensions. — Length of the shell 0-2, breadth OIG ; length of the spines 0-05, basal breadth O'Oo. 



Habitat. — Central Pacific, Station 267, surface. 



(j. Belonas2ns multi/uris, n. sp. 



Parmal )>ores circular, of the same size as the circular sutural pores. Each jilate surrounded by 

 fifteen to eighteen sutural pores (three on each side). Spines compressed, about as long as the 

 rarUus. By-spines very numerous, zigzag, half as Icmg as tlie radius. 



Dimensions. — Length of the shell 0-22, breadth 018 ; length of the spines 012, basal breadth 

 0-012 ; length of the by-spines O'OO. 



Habitat. — Equatorial Atlantic, Station 347, surface. 



Genus 373. Dictyaspis,^ n. gen. 



Definition. — B e 1 o n a s p i d a with forty parmal pores (two on each plate), without 

 l)y-spiues, but with a network of prominent crests on the dimply surface. 



The genus Dictyaspis repeats among the Belonaspida the characteristic structure of 

 Cerias'pis (among the Dorataspida), by the development of prominent crests forming a 



' Didya vii = Net-shield ; Iiktvov, ocdw/'s. 



