BY E. F, KALLMANN. 463 



Loc. — Great Australian Bight. 



External features. — The single specimen (PI. xxi., fig. 1) is of 

 luxuriantly arborescent habit, and measures 360 mm. in total 

 height, being thus the largest example of the genus yet obtained; 

 the number of its ultimate branches exceeds one hundred and 

 tifty. The branches are elongated and relativel}' slender, gradu- 

 all}' tapered, distall)- nuich attenuated and flagelliform ; the 

 stoutest are at most S nnn. in diameter at their base. They are 

 richly ami, in places, intricateh' anastomosed, forming thus, as 

 well as b}' their uudtitude, a dense and somewhat tangled mass. 

 Unfortunately the specimen, although in alcohol, is not very 

 perfectly preserved, owing to its having temporarily become par- 

 tially dried (through breakage of the vessel containing it) \\hile 

 in course of transit from tlie collecting ground. In consequence 

 of this — mainly, if not solel}' — the branches are without exception 

 much wrinkled longitudinally, presenting a shrivelled appear- 

 ance: in life, apparently, their outline in cross-section was cir- 

 cular. The dei-mal layer, notwithstanding, remains intact, and 

 exhibits no outward indication of having been detrimentally 

 affected : it has the form of a dense and tough, opaque membrane 

 or skin, with an outward appearance and texture much resembling 

 that of rubber; is composed almost entirely of closely crowded 

 spirula? \ and is even now (after possible shrinkage) usually 

 between 90 and 120//, and occasionally as much as 140/x, in 

 thickness. Into the dermal membrane the skeletal fibres do not 

 enter, nor do their extremities ever cause the surface to appear 

 granular. 



Examined with the naked eye, a transverse section of a branch 

 shows, superficially, a sharply delimited dense layer, 0*2 to 0*4 nnn. 

 in width, the appearance of which is extremely suggestive of a 

 cortex. Under the microscope, however, the seeming cortex is 

 seen to consist in part of a layer belonging to the choanosome, 

 which layer, unlike the I'emainder of the choanosome, is so densely- 

 packed with parasitic algal rods as to assume a whitish-opaque 

 appearance similar to that of the dermal layer itself. But, in all 

 probability, this is not a constant feature. 



