REPORT ON THE RADIOLARIA. ' 709 



Genus 313. PJwrticium,^ Haeckel, 1881, Prodromus, p. 464. 



Definition. — P li o r t i c- i d a with irregular cortical shell of simple lattice-work, 

 enclosing a lentelliptical Xai'naci7Za-sliaped medullary shell. 



The geuus Phorticium comprises all Phorticida in which the irregular cortical shell 

 is formed by simple lattice-work, not by spongy framework. We can divide- this 

 genus into two subgenera : in Pliortopijle (as in the Pylonida) the lattice-work of the 

 cortical shell exhibits large openings or gates ; in Phortolarcus these gates are perfectly 

 closed by network; the former may be regarded as abnormal or irregular Pylonida, the 

 latter as modifications of Larnacida. 



Subgenus 1. Pliurtopyle, Haeckel. 



Definition. — Lattice-work of the irregular cortical shell incomplete, ^^^th large 

 openings or gates, 



1. Phorticium pijlonium, n. sp. (PI. 49, fig. 10). 



Cortical sheU u-regular, roundish, about three times as large as the enclosed lentelliptical, 

 regular, Larnacilla-s\i&l\, connected with it by some radial beams and irregularly latticed girdles ; 

 between these remain four to eight large open gates of irregular roundish form and size ; and these 

 gates are the same as in Tdrapylc and Octopijlc. This very variable species may be regarded as a 

 monstrosity of those genera of Pylonida ; it is very common, but all individuals are more or less 

 unequal ; some specimens approach to some common species of Tetrapyle. The surface of the shell 

 is more or less spiny. 



Bivunsions. — Diameter of the irregular cortical shell ()12 to 0'18 ; length of the lentelliptical 

 medullary shell 0-05 to 0-06, breadth 0-035 to 0-45. 



Hahitat. — Cosmopolitan ; ]\Iediterranean, Atlantic, Pacific, &c., common, surface and in various 

 depths. 



2. Phorticium spironium, n. sp. 



Cortical shell irregular, rouncUsh, tulierous, about four tunes as large as the enclosed subregular 

 Larnacilla-sh&W., connected with it by some irregular radial beams, and by opposite, spirally begin- 

 ing, u'regularly latticed girdles, comparable to those^ of Spironium; between them remain six to twelve 

 large open gates of irregular size and form. Surface rough. The resemblance to some forms of 

 Spironium makes it probable that this species is a deformity or monstrosity of that genus. 



Dimensions. — Diameter of the irregular cortical shell 0-12 to 0'2, of the lentelliptical medullary 

 shell 0-03 to 0-06. 



Hahitat. — Pacific, central area. Stations 270 to 274, surface, and in various depths. 



1 Phorticium = Small vessel ; (porrixiov. 



