KEPOKT ON THE EADIOLARJA. 190 



two to eight times as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 4. Main 

 spines three-sided prisuiatie, with prominent, often somewhat contorted edges, at the distal end 

 cuspidated : longer than the radius of the outer shell. 



Dimendoiis. — Diameter of the outer shell 01.5, middle 0*07, inner O'O;!") ; cm-tical pores 

 0-01 to O'On, bar.s 0-04; leugtli ..f tlie six spines nil, basal breadth O-O.'l. 



Habitat. — Mediterranean (]\lessina), surface ; Canary Islands (Lanzerote); Haeckel. 



24. Hcxacuiitmiu penphvtuin, n. sp. 



Cortical shell double, enclosing a shuple medullary shell. Radial proportion of the three shells 

 = 1:4:5. Inner cortical shell thick walled, with irregular roundish pores, two to eight times as 

 broad as the bars ; five to seven on the radius. Numerous radial spines, arising from it, are 

 connected below their distal ends (at equal distances from the centre) by delicate branched threads, 

 and so form an outer, irregular, thin, cortical shell, with spiny surface. Six main spines three-sided 

 pyramidal, about as long as the radius. 



Diinciisions. — Diameter of the outer shell 0"2l', middle Wl, inner (l'ij4.5 ; cortical pores (of both 

 outer shells) D'Ol to l)-0:!, burs O'OOl to 01105; length of the spines O'l, basal lavadtli (I-IIL'. 



Habitat. — Nurth I'acilic, Station 241, surface. 



Genu.s 80. Ilcxadcnd ron,^ Haockol, 1881, Prodromus, p. 452. 



Dc/iiutuin. — (.' u b o s p h a3 r i il a with three cuuceiitric Jatticu-sphercs and six 

 brauched spines of eipial .size. 



The geutLS Hcvadendron differ.s from HexacontiiDu iu the ramification of the .six 

 dimeusive spines, and from the similar Hexaacistra in the duplication of the medidlaiy 

 yliell. As in the latter instance, each spine can Ijear either three simple hiteral branches 

 or three rows of pinnate lateral branches. 



1. Ilexadendron qiiadricu.sjtis, n. sp. 



All three shells spherical, with radial proportion = 1 : 2 : 6. Pores of both medullary sliells 

 regular circular, twice as broad as the bars. Pores of the cortical shell ii-regular roundish, four to 

 six times as broad as the bars; surface a little thoi'ny. Six radial spines jaismatic, with three 

 ]irominent wing-like edges, which are prolonged below the distal end in three curved lateral 

 branches. (Differs fi'om Hamlonchr quadricusjyis, PI. 22, tig. 11, mainly in the double medullary 

 shell.) 



DiiuLiisions. — Diameter of the outer shell Q-lo, middle 0'U5, inni'r O-025 ; length of the spines 

 012, breadth 0-01. 



Hahitat. — Central Pacific, Station 272, depth 2(300 fathoms. 



' Hucadoiidi-ua = H\n:l\ with si.'C livu.-; : iiuli^oi-ij. 



