42 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 1 1 



very fine grained and does not present any well-defined structure. The 

 gross cavities are rare and too small to be easily seen with the naked eye. 



The first megascleres are plagiotriaenes or diaenes about 40 /a by 

 2,000 /x. Occasional triaenes, which are almost calthrops, are also found 

 as are small oxeas about 20 jx by 600 jx. These latter are usually dermal. 



The principal microscleres are sterrasters, which are modified into the 

 disc shape that differentiates this genus so markedly from Geodia. These 

 spicules are large, averaging 240 /a in diameter. Second microsclere is a 

 very abundant sterraster only 9 ju, in diameter. A third type is a spheraster 

 which is typically 15 /x in diameter. There are also present microstrongyles 

 3 /A by 60 {X. 



Holotype. — ^AHF no. 23. 



Type locality. — ^West of Isla Partida; 140 m; rock bottom. 



Distribution. — Same. 



Material examined. — 

 Sta. 560-36 Isla Partida 3- 9-36 140 m 



Remarks. — This species is unique chiefly because of the enormous size 

 of the sterrasters. No other species has sterrasters which compare with 

 them. 



The species E. alleni de Laubenfels is similar but has much smaller 

 sterrasters and lacks the long plagiotriaenes. It is West Indian. E. proxi- 

 mus Dendy from the Indian Ocean is similar but has strongyles in addi- 

 tion to oxeas and it also lacks the large sterrasters. 



Genus GEODIA Lamarck 



Geodia mesotriaena Lendenfeld 



Plate 80, Fig. 160; Plate 81, Figs. 161, 162; Plate 82, Figs. 163, 164 



Cydoniu?n mulleri Lambe, 1892, p. 72. 

 Geodia mesotriaena Lendenfeld, 1910, p. 96. 



Diagnosis. — Sponges in this species have the characteristic armor of 

 the family. When young the sponge is subspherical, but as it grows it 

 spreads laterally into a massive cake. There is always a spicule plush 

 present, sometimes two or more cm long, although this is frequently 

 rubbed off or damaged. Where the plush is not too dense, special pore 

 areas are found. The general endosomal structure tends to the radiate. 



The following analysis gives the types of spicules found in G. meso- 

 triaena and an indication of sizes to be expected : 



Diacts (usually oxeas), often several mm long; plagiotriaenes and 

 diaenes, often several mm long; ana- and protriaenes, several mm long 

 (known as long as about 22 mm) ; dermal oxeas or styles, about 200 /a; 

 sterrasters, 50 jtx to 100 /x plus. 



