412 "PKOF. J. A. THOMSON AND MK. W. D. HENDERSON ON [Apr. 10, 



Xenia quinqueserta May. 



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

 lefer a colony Avith a smooth cylindiical stalk 1.5 mm. long by 

 4 mm. in diameter. The polyps ai'fe crowded in a kind of capi- 

 tulurn, and are, apart from the tentacles, 11 mm. long. The 

 tentacles are 3"5 nun. in length and bear 3-5 rows of short 

 conical jiinnules on each side of the well-marked bare streak. 

 There are about 20 pinnxdes in each row. No calcareous bodies 

 were seen, but tliere are abvindaiit zoochlorella'. 



It does not seem to us that X. qui nquesertaM :iy is well defined 

 off fi-om X. sansibariana May, and we suspect that both may be 

 varieties of X. umbeUata 8avigny. 



Locality. Chuaka. Previously from Tiuidj;\tu. 



Xenia membranacea iSchenk. 



To this species we refer 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 triangidai- space at the base, and leave a baie 

 stri}) 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. 



Localit}/. Shore, Zanzibar. Pro\ iously recorded from Ternate 

 [Schenk) and New Britain (Ashivorth). 



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. 

 Thei-e is a free streak on both siu-faces. The jiinnules ai'c slender, 

 cylindrical, and truncate. The l)ody of the polyp was 4 mm. in 

 length, the tentacles were about the same. 



Another specimen is distinguished Ijy the thickness of the 

 polyps (2-5 mm. to a length of 9), by the long truncate pinnules, 

 numbering al)Out 24 in each row. In both specimens the colour 

 in spirit was white. 



Locality. Shore, Zanzibar. Previously recorded from Red Sea 

 {^Khmzingei') and Indian Ocean {JJourne). 



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 

 pinnides aie leduced to wai-ts neai- the base, but soon become 

 shoit cones. There are about two dozen in each row. 



It (lifters from Schenk's desciiption, (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. 



