412 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, 



Xenia quinquesbrta May. 



To this species, though its validity seems to us doubtful, we 

 refer a colony with a smooth cylindi-ical stalk 15 mm. 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 tliere are abundant zoochlorellae. 



It does not seem to us that X. quhiqueserta 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 refei- several small specimens found spread- 

 ing over the branches 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, witli an avernge 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 

 i^Sckenk) and New Bi'itain (^Ashworth). 



Xenia ccerulea 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 sui'faces. 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 by the thickness of the 

 polyps (2'5 mm. 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 pinnvdes 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 (6) in having no supporting trunk, 

 but only a membranous stolon spi-eading 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. 



