AICTONABIA. 351 



27. Solanderia, ? sp. 



An apparently dead and bleached specimen of considerable size 

 seems to belong to tbis genus, and is decidedly distinct from tbe 

 Soutb-African species called by Gray Homophyton gattyce ; but I 

 prefer to await better specimens before describing it, as members of 

 this family appear to rapidly lose their natural characters when 

 dying in the sea. 



Hah. Thursday Island, Torres Straits, 4-5 fms. 



ICILIGORGIA. 



Ihichassaing de Fonhressin, Revue des Zoophytes et des Spongiaires des 

 Antilles (Paris, 1870), p. 12. 



Central spicular axis dense, imperforate. Longitudinal canals 

 forming a circumaxial zone. Erect, branched ; stem and branches 

 antero-laterally compressed, with knife-like lateral edges. Zooids 

 wholly retractile, arranged in single series along each edge of the 

 branches ; no external verrucae. 



To this hitherto exclusively West-Indian genus appears to belong 

 the following species : — 



28. Iciligorgia orientalis. (Plate XXXVII. figs. P-F", 

 and PiATE XXXVIII. fig. e.) 



Stem long, slender, transversely expanded, with a median rounded . 

 ridge running down each of the anterior and posterior faces ; the 

 lateral margins formiilg two even knife-like edges, in grooves in 

 which the zooids lie. Branching apparently normally dichotomous, 

 in same plane as the long diameter of the stem. Branches oval, trans- 

 versely expanded, like the stem, but without the median rounded 

 ridge possessed by the stem, except near the origins of the main 

 branches. The transverse diameter of both stem and branches is to 

 the antero-posterior as 2 : 1. Surface even, feeling slightly rough to 

 the finger. Zooids uniserially arranged, about -5 miUim. in dia- 

 meter, '5 millim. apart, set in a narrow continuous lateral groove of 

 the stem and branches. Colour of stem in spirit pinkish yellow, of 

 branches cream-colour. 



In transverse section the stem and branches are seen to consist of 

 a cylindrical central (" medullary ") spicular axis of closely aggre- 

 gated but distinct spicula, occupying from four fifths (at the base of 

 the stem) to one half (at the apex of the branches) of the entire 

 thickness. The cortical layer is similarly constituted ; it is sepa^ 

 rated from the medulla by a single annular series of four to six 

 circular or oval longitudinal canals, varying in diameter from about 

 •15 millim. near the terminations of the branches to -3 miUim. at 

 the base of the stem. Spicules of medulla, chief forms : — (i.) Roughly 

 fusiform, with few irregularly scattered, mostly fungiform, compound 

 tubercles ; size about '28 to -45 by "087 millim., the largest tubercles 

 about "024 millim. in height, (ii.) Elongated, cylindrical, rounded 



