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



Subgenus 2. Phortolarcus, Haeckel. 



Definition. Lattice-work of the irregular cortical shell complete, without large 

 openings or gates. 



3. Phorticium deforme, n. sp. 



Cortical shell irregular, roundish or longish, three times as large as the enclosed subregular, 

 lentelliptical Larnacilla-shell, connected with it by two opposite latticed wings (the halves of the 

 transverse girdle of Tetrapyle). Network of the cortical shell irregular, dense, perfectly closed, 

 without larger openings or gates. Surface thorny. (May be regarded as a monstrous form of 

 Larnacalpis.) 



Dimensions. Diameter of the irregular cortical shell 015 to 018, of the medullary shell 0'04 

 to 0-06. 



Habitat. Pacific, central area, Station 272, depth 2600 fathoms. 



4. Phorticium abnorme, n. sp. 



Cortical shell irregular, roundish, tuberous, with five to ten quite irregular or nearly hemi- 

 . spherical protuberances, which resemble the cupolas of Zonarida. The regular lentelliptical 

 Larnacilla-she\l is one-third to one-fourth as large as the enclosing cortical shell, and is connected 

 with it by some irregular radial beams. Lattice-work completely closed, without gates. Surface 

 spiny. (May be regarded as an anomalous form of Zonidium; as in the other species of this variable 

 genus, the individuals are very unequal.) 



Dimensions. Diameter- of the irregular cortical shell 012 to 0'2, of the medullary shell O'O.S 

 to 0-05. 



Habitat. Atlantic and Pacific, tropical zone, surface, and at various depths. 



Genus 314. Spongophortis, 1 Haeckel, 1881, Prodromus, p. 464. 



Definition. P horticida with irregular cortical shell of spongy framework, 

 enclosing a lentelliptical Larnacilla-shnped medullary shell. 



The genus Spongophortis differs from Phorticium in the spongy framework of 

 the cortical shell. This encloses the inner Larnacilla-sli&ped medullary shell either 

 directly, or both shells are separated by a hollow interval, and connected either by radial 

 beams or by latticed lamellae. Perhaps both these subgenera might be better separated 

 as genera. 



1 Spongophortis = Spongy vessel ; triroy/os, <fon's. 



