AULOSACCUS SCHULZEI. Ill 



oval in section, measuring about 110 mm. across. Here the wall 

 is 35-50 mm. thick, the gastral cavity opening by an elongate 

 aperture of 35 mm. by 20 mm. 



The greater part of the dermal skeleton has fallen off. Where 

 it is preserved it shows an exceedingly delicate dermal layer 

 supported below by fine hypodermal strands that intersect one 

 another at various angles (PI. VIII., fig. 26). The latticework 

 of the former is scarcely perceptible with the naked eye ; the 

 latter form irregular meshes of various sizes, generally under 

 2 mm. in lengtli of a side. The dermal skeleton must have given 

 a tolerably smooth surface to the sponge. It easily breaks off in 

 flakes in the dried state. The subdermal space seems to be of 

 an inconsiderable width. 



The parenchymal mass, exposed on the outside by abrasion, 

 presents a curly appearance, not unlike that of a wiry fur. The 

 apertures to incurrent canals are medium-sized or smaller. 



The gastral surface is very well preserved. It is lined all 

 over with a continuous layer of the delicate endosomal skeleton. 

 This consists of a small (generally 1-1 è mm.) and irregularly 

 meshed latticework of thin hypogastral strands bearing the gast- 

 ralia whicli, without forming a continuous layer by themselves, 

 leave the hypogastral meshes more or less freely open. Seen 

 under the lens, the gastralia are arranged for the most part 

 in a row on the hypogastral strands with tlieir paratangentials 

 standing out free at right angles on l^oth sides of the latter, 

 thouo;h here and there several of them mav lie side bv side so 

 as to form with their paratangentials small irregular patches of 

 a quadrate-meshed latticework. Taken altogether the arrange- 

 ment of the gastral skeleton resembles that in Accuithascus cactus 

 as shown in PI. XL, fig. 16, though it is more delicate. It 



