826 THE VOYAGE OF H.M.S. CHALLENGEE. 



Subgenus 1. Coscinasparium, Haeckel. 

 Definition .—?\a.t&!i of the shell smooth, without crests, not climj^ly. 



1. Coscinasiyis 2)eri23ora, n. sp. (PI. 138, fig. 1). 



Shell thill walled, with smooth surface, without crests aud dimples, perforated hy pores of very 

 different sizes. Forty aspinal pores, roundish or elliptical, of ahout the same size as the fifty or sixty 

 vioHii-shaped sutural pores, and three to four times as broad as the small roundish coroual pores, 

 which are irregularly formed and distributed, four to eight occurring on each plate (altogether one 

 luunlred to one Inindred and twenty). Eadial spines roundish, somewhat compressed ; inner and 

 outer half nearly of the same length. 



Dimensio)is. — Diameter of the shell 0-12, aspinal pores 0-01 to 0'012, coronal pores 0'003. 



Habitat. — North-West Pacific, Station 235, surface. 



2. Cosciiiaspis stigmopora, n. sj). 



Shell very thin walled, with smooth surface, without crests and duuples, perforated by pores of 

 very different sizes. Forty aspinal pores, roundish, of about the same size as the fifty or sixty violin- 

 shaped sutural pores, their diameter being about one-fifth of that of the plates. Coronal pores very 

 numerous (two hundred to four hundred) and very small, irregularly scattered, ten to twenty occurring 

 in each plate. Sutures strongly denticulated. Eadial spines very thin and short, cylindrical. 



Dimensions. — Diameter of the shell 012 to 015, aspinal and sutural pores 0-01, coronal 

 pores 0-001 to 0-003. 



Hahii-at. — North Pacific, Station 257, surface. 



3. Coscinaspis rhacopora, n. sp. 



Shell very thin walled, with smooth surface, without crests and dimples, perforated by \'ery irre- 

 gular pores of very different sizes aud forms ; commonly more or less lobed or sinuate. Forty 

 aspinal pores and fifty to eighty sutural pores, larger than the numerous (one hundred to two 

 hundred) irregularly scattered coronal pores. Sutures very sinuate. Eadial spines cylindrical, thin 

 and long. • 



Dimensions. — Diameter of the shell 1-15 to 0-18, aspinal and sutural pores 0-01 to 0-02, coronal 

 pores 0-001 to 0-005. 



Huhitat. — Central Pacific, Station 274. 



4. Coscinaspis coscinopora, n. sp. 



Shell thin walled, with smooth surface, without crests and chmples, perforated by very numerous 

 pores of circular form, but of different sizes. Forty aspinal pores and one hundred to two hundred 



