1904. J FROM EAST AFRICA AXD ZANZIBAR. 287 



the largest ineasui'es 8 mm. l«ng by 2 broad. The pericardial 

 prominence is large. The cerata, which are not at all caducous, 

 are set on low inconspicuous ridges in groups as follows : — 



Left. Rhjht. 



First group 8 10 



Second ., 5 4 



Third „ 5 5 



Fourth ,, 5 5 



Fifth „ 3 3 



The smaller specimen has only four groups of cerata, as in the 

 Plate XVI. The first group is composed differently from the 

 others, and possibly consists of two fused together. The cerata 

 are longish, but, as preserved, slightly inflated in the middle. The 

 innermost and outermost are smaller and the median ones largest, 

 attaining a length of 2 mm. The tentacles are longer than the 

 rhinophores, which are not perfoliate. The foot is produced 

 anteriorly into tentacular angles. 



The jaw bears 20-27 distinct coarse denticles of very irregular 

 shape. There is a single series of 18 teeth, of the form usual in 

 Faceliiia, with a strong central cusp and 10-11 longish, some- 

 what curved denticles on either side. 



I cannot see what is the difterence between the geneiu Hervia 

 Bergh (1871) and Rkzolia Trinchese (1877), and refer this 

 specimen to the f oiiner, since it has priority. But it might equally 

 well be referred to Rizzolia. 



Phidiaxa tenuis, sp. n. 



Two specimens f i-om Wasin Island, British East Africa, dredged 

 in 10 fathoms. The notes on the living animal are as follows: — 

 " About half an inch long and very narrow, vermiform. Tail 

 long, but bearing cerata to the tip. These are nearly all lost, 

 but were uniformly vei-milion in colour. Foot white, body 

 pinkish, tentacles and rhinophores white. Foot very narrow 

 behind, broader in front, where it is bordered by a flap on either 

 side ; grooved in fi-ont ])ut not produced into tentaculai- angles. 

 Tentacles very long and spreading outwards. Rhinophores very 

 slightly ringed in the distal halves, which are opaque, the proximal 

 halves being translucent." Of a second specimen caught in the 

 same place next day, it is noted that when it was fii'st captiu-ed 

 •' the cerata looked vermilion and light violet-blue, but subse- 

 quently became practically coloui-less with a bluish bloom. The 

 vermilion liver does not nearly fill the cerata ; it is thin and has 

 numerous short more or less horizontal branches. In this specimen 

 the tentacles and i-hinopliores appear of nearly the same length." 



The preserved specimens are of a uniform dii^ty yellow, and the 

 largest is 9 mm. long and 2 broad. Both of them have lost 

 nearly all their cerata, and the disposition of these organs is no 

 longer plain, but apparently they were set in five gi'oups, without 



