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Show 1900.] MARINE FAUNA OF CHRISTMAS ISLAND. 129 CLATHRINA PRIMORDIALIS (Haeckel). 1872. Ascetta primordialis var. protogenes Haeckel (6. ii. p. 16, Atlas, pi. ii. fig. 13). * 1892. Clathrina primordialis Lendenfeld (8. p. 195). The specimen consists of a small mass about 10 m m . in area by 5 m m . in height. No oscules are visible, but this is probably due to the contracted state of the sponge. The spicules, which are equiangular and equiradiate, are very small and slender, being smaller than in the typical Mediterranean form, and much smaller than in the Australian form named Clathrina primordialis var. protogenes by Carter (3. p. 510) and C. protogenes by Dendy (5. p. 58). The rays, which are 70 p. by 6p, taper gradually to a rather sharp point. LEUCANDRA sp. The specimen forms a small oval mass 3 x 2 m m . plugging up an oscule of Tetilla ternatensis. The outer surface bristles with the projecting ends of stout oxeotes which pass through the dense mass of tri-radiates ; gastral quadri-radiates can here and there be made out in spaces in the interior. Spicules. Oxeotes 1500 x 70^/ ; tri-radiates, rays sharp-pointed, often wavy, 245 x 8 p ; quadri-radiates, tangential rays curved inwards towards the apical ray ; tangential ray 105 x 18 p, apical ray 35 p. in length. Canal-system : pores lead into incurrent spaces surrounding groups of large oval ciliated chambers 85 p in diameter, and groups of the latter open into excurrent spaces. The species is probably new ; but since the specimen is verv small and has been damaged in extraction, owing to its being partly involved in the tissues of the Tetilla, no specific name has been given. CHONDROSIA RENIFORMIS Nardo. One typical specimen occurs ; it is bluish black on the upper surface; pale brown below, where it is attached by a narrow ridge to the rock. The one rather large oscule has a membranous slightly serrated margin. The colour on section is dirty white. I have examined some fragments of tbe type specimen of Chondrosia ramsayi Lendenfeld, and agree with Topsent in regarding this species as a synonym of C. reniformis. A noticeable feature in the Australian specimen is theabundance of pigment in the interior, giving the sponge a slaty colour on section. Distribution. Mediterranean ; Kattegat; Tadjurra, Gulf of Aden ; Port Jackson ; Amboina ; Christmas Island ; Galapagos Islands. C H O N D R O S I A PLEBEJA O. Schmidt. 1868. Chondrosia plebeja O. Schmidt (14. p. 1). There are eight specimens, seven in alcohol and one in formol; PROC. ZOOL. SOC-1900, No. IX. 9 |
