416 COLLECTIONS FIIOM MELANESIA. 



or the tubes arc almost level with the edge of a wall-like ridge 

 which terminates the sponge above ; margin of tubes simple. 

 Surfaco of sponge between the coarse inequalities smooth, imper- 

 forate to naked eye. Texture in spirit firm but brittle ; colour 

 dull and pale umber-brown. 



Main skeleton — very loose primary lines of spicules, about three 

 spicules broad, running irregularly towards surface, crossed by 

 secondary tracts of similar character, 2 or 3 spicules broad, at right 

 angles to the primaries and about '4 millim. apart. Dermal 

 skeleton — extremely loose tracts of irregularly parallel spicules, 

 3 or 4 spicules broad, surrounding roundish or polygonal areas 

 from '18 to -28 millim. in diameter. Barcode dense, granular, 

 yellowish brown, containing much foi'eign material. Spicules 

 smooth acerate, slighly curved, tapering to fairly sharp points from 

 centre, more rapidly towards the ends than near the centre ; size 

 •4 by -019 millim. 



Hah. Port Darwin, N. coast of Australia, 7-12 fms. ; bottom 

 sand and mud. 



The vertical and horizontal dimensions of the irregular lobes both 

 vary from about 12 to 22 millim. The specimens are all broken ; 

 the greatest length represented among the pieces is 60 millim. 

 (2^ inches). By the very slight extent to which the tubes which 

 chiefly characterize the genus are developed, the species is distin- 

 guished from S. dura, Schmidt; by the large size of the skeleton- 

 spicules, from S. aulopora. It has somewhat the general habit of the 

 specimen figured by Schmidt (Atl. Geb. pi. v. fig. 8) for the latter 

 species, and of Thalysids subtrianyidaris, Duch. de Fonbressin and 

 Michelotti ; but has a more contort character than the latter, and 

 the spicules are far larger than those of the former. It is also quite 

 distinct in habit and spiculation from the form termed Thah/sias 

 triangularis by Carter (Phil. Trans, clxviii. p. 287), from Kerguelen 

 Island, the spicules in this being (as I have ascertained from the 

 original specimens, now in the Museum) only *19 to *2 by - 014 to 

 •016 millim. in dimensions. In Schmidtia (Isodictya, Bowerbank) 

 mirabilis, Bowerbank, another Indo-Pacific species, the spicules are 

 only about half tho size of the present species, although the habit is 

 similar. It is perhaps nearly allied to S. elavata (Balsamo-Crivelli), 

 Esper, by its general habit and large strong spicules ; but those of 

 that species, as figured by Balsamo-Crivelli (Atti Soc. Ital. v. pi. iv. 

 fig. 12), are considerably stouter than those of S. variabilis. 



52. Amorphina megalorrhaphis. 



Carter, Ann. $ May. N. H. (5) vii. p. 368. 



A remarkable small specimen, which at first sight appears to be 

 pcdicillate, with a fusiform head, but is in reality horizontal in 

 growth. It is a subfusiform mass, which tapers rapidly to a blunt 

 point at one end, runs out as a long narrow cylindrical lobe at the 

 other, and is attached by one side of its thickest part, so that the two 

 ends mentioned, project horizontally outwards to right and left of tho 



