OCR Text |
Show 412 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, XENIA QUINQUESERTA May. To this species, though its validity seems to us doubtful, we refer a colony with a smooth cylindrical stalk 15 m m . long by 4 mm. in diameter. The polyps are crowded in a kind of capi-tulum, and are, apart from the tentacles, 11 mm. long. The tentacles are 3*5 mm. in length and bear 3-5 rows of short conical pinnules on each side of the well-marked bare streak. There are about 20 pinnules in each row. No calcareous bodies were seen, but there are abundant zoochlorell?e. It does not seem to us that X. quinqueserta May is well defined off from X. sansibariana May, and we suspect that both may be varieties of X. umbellata Savigny. Locality. Chuaka. Previously from Tumbatu. XENIA MEMBRANACEA Schenk. To this species we refer several small specimens found spreading over the blanches of an alga. They agree in having 3-4 rows of pinnules which cover the oral surface of the tentacles except a small triangular space at the base, and leave a bare strip up the aboral surface. There are 15-20 slender conical pinnules in each row. The bodies of the polyps are about 5 mm. in length, with an average width of 0*75 ; the tentacles are 4-5 mm. in length. There are small polyps at the bases of the full-grown individuals. Locality. Shore, Zanzibar. Previously recorded from Ternate (Schenk) and New Britain (Ashworth). XENIA COERULEA Ehrenberg. To this species we refer a small specimen with two rows of uniform pinnules on each side of the middle line of the tentacle. There is a free streak on both surfaces. The pinnules are slender, cylindrical, and truncate. The body of the polyp was 4 mm. in length, the tentacles were about the same. Another specimen is distinguished l>y the thickness of the polyps (2*5 m m. to a length of 9), by the long truncate pinnules, numbering about 24 in each row. In both specimens the colour in spirit was white. Locality. Shore, Zanzibar. Previously recorded from Red Sea (Klunzinger) and Indian Ocean (Bourne). XENIA TERNATANA Schenk, var. ELONGATA, nov. To this species we refer a specimen with long slender polyps, long flat tentacles, and two rows of pinnules on each side. The pinnules are reduced to warts near the base, but soon become short cones. There are about two dozen in each row. It differs from Schenk's description, (a) in the great length of the polyps (10-19 mm.); and (b) in having no supporting trunk, but only a membranous stolon spreading among seaweed. If emphasis is laid on the nature of the pinnules and the number of rows, the specimen may be fairly placed beside X ternatana. Locality. Chuaka. |