REPORT ON THE RAD10LARIA. 709 



Genus 313. Phorticium, 1 Haeckel, 1881, Prodromus, p. 464. 



Definition. P horticida with irregular cortical shell of simple lattice -work, 

 enclosing a lentelliptical Larnacilla -shaped medullary shell. 



The genus 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 Phortopyle (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. Phortopyle, Haeckel. 



Definition. Lattice-work of the irregular cortical shell incomplete, with large 

 openings or gates. 



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



Cortical shell irregular, roundish, about three times as large as 'the enclosed lentelliptical, 

 regular, Larnacilla-shell, 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 Tdrapyh and Octopyle. 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. 



Dimensions. Diameter of the irregular cortical shell O12 to 018 ; length of the lentelliptic.il 

 medullary shell O05 to 0'06, breadth 0'035 to 0'45. 



Habitat. Cosmopolitan ; Mediterranean, Atlantic, Pacific, &c., common, surface and in various 

 depths. 



2. Phorticium spironium, n. sp. 



Cortical shell irregular, roundish, tuberous, about four times as large as the enclosed subregular 

 Larnacilla-shell, connected with it by some irregular radial beams, and by opposite, spirally begin- 

 ing, irregularly 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. 



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



1 Phorticium = Small vessel ; QoTrtxlua. 



