394 coiXECiioNS rnoii Melanesia. 



21. Chalina monilata*. (Plate XLI. fig. h.) 



Erect, dictotomously branched ; branches circular in traifsverse 

 section, round at the ends, solid, 4 to 6 millim. in diameter, swelling 

 out gently, necklace-like, about every 8 or 10 millim. of their 

 length ; terminal ones 35 to 85 millim. long, generally broad and 

 compressed at point of bifurcation. Stem short, no stouter than 

 most of the branches. Surface stnooth, glabrous. Vents circular, 

 edges flush with the surface, diameter about 2 millim., few, scattered 

 irregularly on surface. Texture in spirit compressible, elastic, mode- 

 rately tough ; dermis tough, parchment-like ; colour opaque yellowish 

 brown. 



Main skeleton irregularly rectangular, fibres very flexible, pale 

 amber-yellow ; primaries about -042 millim. in diameter, spicules 

 3- to 47-serial ; secondaries about "035 millim. in diameter, spicules 

 1- to 3-serial : primaries "35 to -od millim. apart at surface, 

 secondaries -14 to -35 millim. Dermal skeleton — a wide-meshed, 

 irregular polygonal network of strong fibre, -035 to -07 millim. 

 thick; spicules numerous, 3- to 8-seriai; within its meshes a dense 

 and regular, usually rectangular, network of very pale horny fibre, 

 •006 to -042 millim. in diameter; meshes -05 to •! millim. in diameter; 

 spicules of fibre usually l-serial : fibres of characters transitional 

 between these two kinds also occur. Sarcode very pale brown, 

 slightly granular. Spicules smooth, acerate, usually tapering gra- 

 dually to fine points, size -1 by -0017 millim. ; more rarely tapering 

 slightly from centre to about two diameters from ends, and then sud- 

 denly to sharp points ; size -085 by -0021 millim. 



Hab. Port Jackson, 0-5 fms. 



Several specimens in spirit, the largest 175 millim. (7 inches) in 

 height. This species has the general habit of Chalina oculata, 

 Pallas ; but the vents are less numerous and regular, the dermis is 

 tough, instead of being soft and velvet-like, and the branches are 

 moniliform, not strictly cylindrical, and the slender acerate spicules 

 are very different from the stout fusiform ones of 0. oculata. I am 

 unable to assign this species to any of the numerous probable Cha- 

 linidse which Lamarck has described under his section " Masses 

 rameuses," &c.t The tough outer layer, the spiculation, or the habit 

 distinguish it alike from these and all other ChalincB with which I 

 am acquainted. 



22. Cladochalina armigera. 

 Tuba armigera, Duch. de Fonhressin 8f MichelotU. 



Two dry specimens and one in spirit. Agree well in external 

 characters with the original figure (Spong. Mer Caraib. pi. viii. fig. 3) 

 and in the characters of the fibre, except that the spicules arc far 

 more abundant (6 to 8 series in the primary and proportionally 



* From Lat. monile n ecMace. 

 t Ann. Mus. Hist. Nat. xx. p. 446. 



