522 EDITH M. PRATT. 



The tentacles (fig. 22 tent.) are very small but are slightly larger than those of Sc. durum, 

 being about "4 mm. long and bluntly conical. They are pinnate, but I have been unable 

 to see more than a single row of pinnules down each side. 



The stumodaeum (fig. 22 s.) is long, and somewhat convoluted and is '6 — '8.5 mm. in 

 length. The siphonoglyjjh is clearly shown in transverse sections. 



The mesenteries are long and slender (fig. 22); the ventral and lateral mesenterial 

 filaments are short and broad and measure about '18 mm. in length (fig. 22 v. m.f., I. m.f.). 

 The dorsal mesenteries are much longer and are broader than the others, have broad grooved 

 ciliated filaments (fig. 22) and are similar to those of other Alcyonaria. 



Ova in all stages of development are present in the mesenteries of one of the frag- 

 mentary specimens from shallow water. They are of the typical Alcyonarian character and 

 are of a yellowish-brown colour. The largest are easily seen with the naked eye. 



Siphonozooids. Whitelegge (1897, p. 220) says of this species, " The Siphonozooids are 

 minute and the orifices difficult to distinguish even with a lens." 



If a thin strip of tissue be taken from the surface of the colony and examined under 

 the microscope the siphonozooids are seen to occupy minute rounded areas surrounded by 

 a spicular tissue containing minute clubs and spindles, as in Sc. capitale (fig. 17). It is 

 only after decalcification and staining (borax-carmine answers very well) that the stomodaea 

 and their apertures can be distinguished (fig. 21). The aperture is often rounded, but it 

 is occasionally keyhole-shaped^. As in other dimoqahic species the siphonozooids terminate 

 posteriorly in the transverse vessels of the superficial canal system (fig. 22). As these vessels 

 lie very near the surface of the colony the siphonozooids are necessarily very short, averaging 

 •17 mm. long. 



The stomodaeum is usually a tiny tube one cell in thickness and one or two cells in 

 length. Sometimes it is a solid cord of cells without lumen so that the siphonozooids 

 have no aperture to the exterior. Traces of mesenteries are not difficult to perceive in some 

 of the siphonozooids. 



Canal Systems. Both superficial and internal canal systems are clearly marked (fig. 22), 

 and may be regarded as being typical of the genus (pp. 518-19). The vessels ramify and 

 anastomose in all directions, so that a complete circulation of fluids is ensured throughout 

 the colony. The vessels near the surface are crowded with zoochlorellae. The transverse 

 vessels lie very near the surface, they are not so broad as the transverse vessels of Sc. capitale, 

 their average diameter being '08 mm. 



10. Sclerophytum hirtum sp. no v. (PI. XXX. figs. 23 — 25). 



A single well-preserved specimen from Naifaro reef, Fadifolu Atoll, having a portion of 

 the stalk with basal attachment missing (fig. 23), 46 mm. high and 66 x 35 mm. broad. 



The stalk is short, broad, laterally compressed, and is much wrinkled vertically, its surface 

 is granular and it yields slightly to pressure. Its height (incomplete) is 22 mm. and breadth 

 45 X 25 mm. The capitulum is irregularly divided into numerous and slightly flexible lobes. 

 The primary lobes or branches vary to a considerable extent in height, breadth, and number 

 of secondary lobes. The mode of branching is irregular; di- or tri-chotomy is frequent, 

 but here and there lateral branches are given off from a common stem, some of these branches 



' These apertures should not be contused witli the lobes left by spicules after decalcification. 



