BY E. P. KALLMANN. 511 



surface is rendered uneven by low, irregular undulations and 

 indistinct, longitudinal furrows. On the upper surface only of 

 the more massive specimens, between the nionticular elevations, 

 there are many oscula-like openings, the appearance of which 

 (although they are plainly seen to be the orifices of main exhalant 

 canals) suggests that they have been caused by laceration of the 

 dermal membrane; and it is possible, therefore, that in the 

 perfect sponge the dermal membrane is continuous across the 

 debouchures of the exhalant canals, thus producing a condition 

 of lipostomy. This may account for the fact that, in the smaller, 

 digitate specimen, oscula were not observable. 



The main exhalant canals run longitudinally upwards through 

 the sponge, increasing in diameter as they ascend; they attain a 

 maximum diameter, in the largest specimen, of about 3 mm., but 

 in the smallest specimen, only of about 1 mm. Many of the 

 canals, especially in the upper part of their course, run for a 

 considerable distance immediately below the surface, their outer 

 wall consisting of scarcely more than the dermal membrane 

 Immediately underlying the dermal membrane, also, there are, 

 elsewhere, numerous and fairly extensive incurrent spaces. 



The consistency of the sponge in alcohol is firm, fairly tough, 

 compressible, and resilient ; and the colour varies from pale 

 cream to light yellowish-brown. The colour in life, as recorded 

 in the case of a single specimen by Dendy, is "cinnamon, [with] 

 the projections deep chrome." The skeletonised sponge is very 

 loose-textured, and not of uniform density (PI. xxxi , fig.l): the 

 coarseness of the fibres is about the same as in A. plicata, but, 

 in the present species, the skeleton is of considerably smaller 

 bulk relatively to the bulk of the entire sponge. 



The dermal membrane — owing partly to the many spaces im- 

 mediately underlying it, and partly to its being of considerable 

 thickness — is very distinct, and, except on the upper surface of 

 the sponge (i.e., in the region of the oscula-like openings) pre- 

 sents a minutely reticulate appearance due to the mode of 

 arrangement of the dermal pores (PI. xxxviii., tigs. 1-4). The 

 reticulate pattern is conspicuous, even to the naked eye, in the 

 two massive specimens, but requires a lens for its detection in 



