1906.] ALCYONARIANS FROM ZANZIBAR. 407 



by narrow stolons but mainly by a coherent membrane. The 

 polyps may attain a length of 5 mm., not including the tentacles, 

 which are usually about 3 mm. long. The breadth of a fully- 

 extended polyp is slightly under a millimetre. Some of the 

 polyps have their tentacles wholly retracted, and ai-e themselves 

 contracted into sugar-loaf- like prominences about 3 mm. in height. 

 There is no evidence of calcai'eous bodies either in tentacles or 

 polyps, and the colour of the pi'eserved specimen is ti-anslucent 

 white. 



The most characteristic features are presented by the tentacles. 

 They measure almost half a millimetre at the base, but narrow 

 somewhat quickly and end in a fine point. They appear to be 

 slightly convex aboi-ally and slightly concave orally. When fully 

 expanded they form a circle about 3*25 mm. in diameter. The 

 pinnules are about nine in number on each side, but the four 

 nearest the base of the tentacle are vei-y short, the longest pinnules 

 being usually numbei'S 4 and 5 from the distal end ; they are 

 separated fi'om one anothei' by short intervals ; and towai'ds the 

 base, beginning at the sixth, there is a gradual shunting from a 

 lateral position on to the oral suiface of the tentacle. In shape 

 the j)innules are cylindiical, and haA^e a somewhat rugose appear- 

 ance due to contraction. 



In another specimen, which had a red coloui- when living, some 

 of the polyps attain a length of 1 mm., not including the tentacles, 

 and are densely packed with eggs and embryos. -In the majority 

 the tentacles and the oesophageal region are completely retracted 

 within the smooth-walled calyx. In some parts of the colony the 

 polyps are connected by narrow stolons about 1 mm. in diameter ; 

 in others there is a continuous membrane. 



Locality. Cape Yerde Islands. 



Olavularia pregnans, sp. n. (Plate XXX. fig. 3.) 



This interesting form is well marked by two peculiarities. In 

 the first place, the pinnules occur all round the tentacles. This 

 unusual arrangement is also seen in G. inflata Schenk, but, apart 

 from the generic chai^acters, thei'e is little else in common between 

 the two species. The second jDcculiarity is that many of the 

 polyps show a large expansion of the body, containing a large 

 embryo or as many as three. 



There is a thin basal membrane growing over a polyzoon. The 

 polyps, sometimes marked by contraction-rings, are about 5 mm. 

 in length and 1 mm. in breadth, with slender tentacles of 2*5- 

 3 mm. in length by 0-35-0'4 in breadth. No bare streak is 

 to be seen on the tentacles, which are surrounded by shoi-t conical 

 pinnules with a kind of spiral ai-rangement. Crowded zoo- 

 chlorellse produ.ce here and there a glistening appearance, but no 

 trace of spicules could be seen. 



Many of the polyps show at a shoi't distance below the tentacles 

 a prominent expansion (2"5 mm. in diameter) of the tube con- 

 taining up to three embryos. As these grow one side of the 



