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



as long as the radius of the shell ; gradually tapering from its surface towards both ends. By-spines 

 very short and numerous, simple. 



Dimensions. Length of the shell 0'13, breadth Oil ; length of the spines 0'08, basal breadth 

 0-025. 



Habitat. Central Pacific, Station 271, surface. 



4. Belonaspis lanceolata, n. sp. 



Parmal pores elliptical, six 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, flat, in the 

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

 zigzag, half as long as the shell-radius. 



Dimensions. Length of. the shell 015, breadth 013 ; length of the spines 014, basal breadth 

 0'03 ; length of the by-spines 0'04. 



Habitat. North Pacific, Station 235, surface. 



5. Belonaspis conifera, 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 016 ; length of the spines 0'05, basal breadth 0'03. 



Habitat. Central Pacific, Station 267, surface. 



6. Belonaspis multiforis, n. sp. 



Parmal pores circular, of the same size as the circular sntural pores. Each plate surrounded by 

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

 radius. By-spines very numerous, zigzag, half as long as the radius. 



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

 0-012 ; length of the by-spines 0'06. 



Habitat. Equatorial Atlantic, Station 347, surface. 



Genus 373. Dictyaspis, 1 n. gen. 



Definition. B elonaspida with forty parmal pores (two on each plate), without 

 by-spines, but with a network of prominent crests on the dimply surface. 



The genus Dictyaspis repeats among the Belonaspida the characteristic structure of 

 Ceriaspis (among the Dorataspida), by the development of prominent crests forming a 



1 Dictya DM = Net-shield ; II'XTVOV, a7ck. 



