PORIFERA. III. 



foundland, 46 50' Lat. N., 50 12' Long. W., depth 82 fathoms and at the Azores in depths of 318 and 

 664 fathoms (Topsent). The species is thus distributed between 74 36' and 38 35' Lat N. and between 

 36 Long. E. and 56 Long. W. The bathymetrical range varies somewhat greatly, from 20 fathoms 

 (Axarfjord, Iceland) to 799 fathoms (station 78, on the eastern slope of the Reykjanaes Ridge). 



Histoderma Cart. 



Sponges of more or less bladder-like consistence; the shape globular or rmmdish in the free, 

 not attached forms, more flattened in the attached forms. The body provided with somewhat long tubular 



fistula 1 , or with shorter or longer papilla 1 . An outer, solid dermal layer present, furnished with a skel- 

 eton of close-lying spicules. The skeleton of the inner body formed of partly regularly arranged, thin 



fibres, not forming a reticulation, or of more scattered spicules. Spongin not present. Spicula: mega- 

 sclera only of one form, the same in the dermal layer and the inner body, they are diactinal, tylota, stron- 



gyla or tornota, sometimes the ends are unequal, the spicules then being tylostrongyla or tylotornata; 

 microsclera; the characteristic microsclera are chelce arcuatce; to these sigmata are generally added, 

 and further trichodragmata may occ^lr ; the sigmata may be of one or two sizes, and a peculiar small 

 chela may occur (namcclligerum). 



i. H. appendiculatum Cart. 

 PI. I Figs. 6- 1 1, PL IV, Fig. 2. 



1874. Histoderma appendiciilatum Carter, Ann. Mag. Nat. Hist. 4. XIV, 22O, PI. XIV, figs. 2325, PL XV, 

 figs. 39 a b. 



Globular or more irregularly tuberous, provided with more or less numerous, tubular fistula; 

 free, not attached. Surface smooth. The body surrounded by a solid, bladder-like dermal layer. Oscula in 

 the apex of some of the fistula, pores in the apex of others. The dermal skeleton formed of close-lying, 

 tangential spicules in several layers; the skeleton of the inner body consisting of thin fibres, running 

 irregularly, being regular only at the surface and parallel with this; there are no transverse fibres. 

 Spicula: megasclera tylota passing by intermediate stages into unequal-ended strongyla, 0-2? 0-95"""; 

 microsclera two forms, chelce arcuatce 0-040 0-046""", sigmata 0-047 o-opj' 



j tntn 



Of this curious and interesting species - - the type on which Carter founded the genus - 

 the Ingolf-Expedition has taken a somewhat rich material. The shape is in the whole as described 

 by Carter; the sponge consists of a globular or tuberous body, from which some few shorter or 

 longer tubular fistuloe issue. The body may be nearly quite globular, which especially seems to be 

 the case with the smaller individuals, but generally it is of a more or less irregular shape, often some- 

 what flattened. The fistulae are, in the specimens to hand, in most cases broken off, only some single 

 ones are whole; they are cylindrical and straight or more or less curved, the sponge thus strongly reminds 

 one of a potato with stolons; it grows freely, without attachment. The body has in the largest speci- 

 men a diameter of 2o mm and in the smallest of 8 mm ; the length of the undamaged fistulse is about 

 25""", they are of the same length in the small as in the large specimens, while on the other hand the 



