360 COLLECTIONS F KOM MELANESIA. 



may be considered characteristic of its habit ; his figure, though 

 taken apparently from a rather stunted specimen, is fair, but the 

 joints arc too long. Lamarck, too, notices the short stem and its 

 sudden division into slender branches, which are its best external 

 disl inguishing characters. In its minute structure it is characterized 

 by its fine Blattkeule with dentate edges and graceful longitudinal 

 verruca-spicule. Dry specimens are apt to turn white ; perhaps the 

 white variety mentioned by Lamarck (I. c.) is an instance of this 

 phenomenon. A variety occurs from Torres Straits with grey cortex, 

 black verruca?, whito internodes, red joints. 



The species figured hy De Blainville (I. c.) differs from ordinary 

 specimens of M. textiformis in its yellow soft joints. It is possibly 

 a variety of M. coccinea. 



34. Mopsella clavigera. 

 (Plate XXXVII. fig. B ; Plate XXXVIII. figs, a-a'".) 



P Mopsella elongata, Studer, MB. Ah. Berlin, 1878, p. 666. 



Corallum branching strictly in one plane ; branches almost inva- 

 riably anastomosing in adult at the soft joints, proportionately less, 

 according to age, in the younger specimens ; the meshes thus formed 

 are either longitudinally elongated or irregularly polygonal ; the 

 frond may be either about as broad as it is high, or the height may 

 be double the breadth. Stem short, moderately developed or weak. 

 Internodes undulating or seldom straight, compressed, the antero- 

 posterior diameter having the proportion with regard to the side 

 diameter of about 3:2; penetrated towards base by longitudinal 

 canals. Soft joints distinct, but not large, elongated near base of 

 main branches, only just perceptible in younger parts. Terrucae 

 numerous, scattered over sides and back (or front) of corallum, but 

 leaving a bare space down the middle of its posterior aspect ; tuber- 

 cular in shape, slightly prominent. Cortex thin, white and almost 

 colourless. Axis of internodes rough, white or pale pink (generally 

 only so in young specimens). Soft joints bright red. pink, or almost 

 colourless. Verrucue dirty brownish to white in colour. 



Spicules of general cortex : — (i.) Coarsely tuberculated, rather 

 bluntly pointed, fusiform, of various sizes, the larger ones some- 

 what swollen, tapering and sometimes terminated by a small " Piatt " 

 at the other extremity : average maximum dimensions 17 to - 21 

 by -07 millim. (ii.) Blattkeule, compound, with about two lancet- 

 shaped lamina), as a rule, and these mainly flattened in one plane, 

 with a short conical to almost obsolete shaft, covered with smallish 

 tubercles often deeply dentate ; average maximum dimensions -14 

 by '07 millim. Spicules of verruca long, slender, curved and pointed, 

 fusiform, with tubercles fewer and less prominent than those of the 

 cortical spicules and less numerous near the ends : average maximum 

 dimensions ■'!'•> by - 026 to - 285 by *U44 millim. 



Hah. Port Curtis, Queensland, 5-1 1 fins., bottom sand and shells : 

 Port Molle, 1-1 fms., bottom rock: Thursday Island, Torres Strait.-. 



