BY E. F. KALLMANN. 409 



to the two last mentioned, because like them and unlike the 

 others (as described), it possesses smaller, scattered anisochelte in 

 addition to those which form rosettes. 



The type-specimen consists of only a few ill -preserved scraps 

 attached to pieces of shell and other debris. This condition of 

 the specimen would lead one to suppose that the species is of 

 encrusting habit, and the manuscript specific name " hicriistans " 

 implies the same. According to Lendenfeld's description, how- 

 ever, the sponge is " composed of anastomosing branches on an 

 average 7 mm. thick." One might conclude, therefore, that the 

 sponge is variable in habit; but, for the present, I think it would 

 be as well to disregard altogether what has been stated concein- 

 ing the outward features of the species, and, for its identification, 

 to rely solely upon skeletal characters. 



Unfortunately, owing to the fragmentary condition of the 

 specimen, several points in connection with the skeleton, of pos- 

 sible diagnostic value, have not admitted of elucidation; among 

 other things, it could not be determined whether, as Lendenfeld's 

 description implies, the reticulate character of the skeleton 

 results simply through the interosculation of dendritically branch- 

 ing longitudinal fibres, or whether it is due to the union of longi- 

 tudinal by means of transverse fibres. 



Description. — The main skeleton is a loose reticulation of 

 spicule-fibres devoid of spongin, the stoutest of which exceed 150/x 

 in diameter. Close beneath the surface, the outwardly-running 

 fibres subdivide each into a number of divergent strands, whose 

 penicillately outspread extremities support the dermal membrane. 

 The dermal skeleton is a wide-meshed, somewhat lattice-like 

 reticulation, the meshes of which, formed by interconnecting, 

 branched, paucispicular fibres, are, as a rule, sparingly subdivided 

 by independent short spicule-strands, and single spicules. There 

 are also present in the dermal membrane a few scattered micro- 

 scleres of the same three kinds as occur interiorly. 



Spicules. — (a). The megascleres in general agree exactly in 

 form with those of P. bidentata{i5); in rare cases, however, the 

 small apical tines are wanting, and the spicule is then a subtylo- 

 strongyle. These tines are usually two in number, occasionally 



