6Y E. F. KALLMANN. 523 



as a rule, are in the same plane, the consequence being a well- 

 marked tendency, most clearly expressed in sparsely-branched 

 specimens, towards a tlabellate disposition of the branches; 

 but with their multiplication in number and consequent dis- 

 placement due to mutual interference, the branches gradually 

 come to assume a more or less regularly arborescent arrangement. 

 The maximum length attained by the branches rarely exceeds 

 80 mm., but is usually greater than 40 mm; occasionally, how- 

 ever, as in the single case of one of the P.P. specimens (PI. xxxiii., 

 fig.2), they remain quite short (even the longest not exceeding 

 25 mm.) and more or less colierent with one another proximally, 

 thus forming, or tending to form, a cluster or "head" of (some- 

 what palmately) lobed or digitate lamellaj. 



The oscula are characteristic, having the form of shallow 

 stelliform depressions, 1 to 2 mm. in diameter, at the centre of 

 each of which is a group of several (usually 3 or 4) minute 

 exhalant orifices; their stellate shape is frequently enhanced by 

 short, shallow grooves radiating from them. Most frequently, 

 they are arranged along the branches more or less distinctly in 

 two rows, but sometimes only one such row is apparent, and 

 sometimes they are in part disposed in a scattered fashion; their 

 arrangement appears generally to be the moie irregular in pro- 

 portion as the branches are the more compressed. In most 

 cases, the oscula are not conspicuous, and they are less evident 

 in the desarcodised than in the perfect condition of the sponge; 

 indeed, in the case of the two washed-out P J. specimens, they 

 were altogether unobservable. 



In general appearance and in texture, the sponge is nearly 

 similar to an ordinary Chaliiiine sponge. The consistency is 

 fairly tough and elastic; moderately soft, but not Heshy; com- 

 pressible and resilient. The colour in life is recorded in the 

 original description as brownish-red or orange-rufous; in alcohol, 

 it varies from pale greyish-yellow to light brown. 



The dermal membrane is extremely thin and delicate, and 

 without spicules; it appears to be very easily destroyed, since, 

 even in the specimens which otherwise are excellently preserved, 

 only portions of it remain. The dermal pores are arranged in 



