98 MARINE BIOLOGY OF THE SUDANESE RED SBA. 
practically no information except the figure, the identification must be some- 
what doubtful. Whatever the animal is called it appears to be a distinct 
species, as Bergh says, and more definitely characterized than most. 
HEXARRANCHUS SANGUINEUS (fiippell & Leuckart). 
(Deris sanguinea, Riippell & Leuckart in Neue Wirbellose Thiere des Rothen Meeres, 
1828, p. 28 = Hevabranchus pretextus, Ehrenberg: Symbole Physic, 1851. 
Cf. Hage : “ Two new Opisthobranchs from the Red Sea,” in Results of Swedish 
Zool. Exped. to Egypt and White Nile, 1901, p. 5.) 
The notes on the living animal say: ‘“‘ Hexabranchus ; seen on the reef 
south side of Tella Tella Saghir at a depth of one fathom and obtained by 
diver. Colour as in the East African variety in which there is no yellow. 
The whole body is pure crimson except the mantle-edge which has the usual 
streak of white.” 
This is the Heaabranchus pretextus of Ehrenberg, the type of which was 
captured at Tor in the Red Sea. The species has been described under 
many other names, and in particular H. anaiteus, Bergh, H. Petersii, Bergh, 
FI, suezensis, Abraham, and HH. plicatus, Hiige, are probably referable to it. 
Hiige in defining the characters of his 7. plicatus, forgets that these animals 
can alter their shape and proportions even in life, and the fact that one 
alcoholic specimen is cireular and another elliptical is not necessarily of any 
specific importance. 
HH, sanguineus seems to be characteristic of the Red Sea but less common 
elsewhere. On the coast of Hast Africa I found it much more rarely than 
the mottled varieties. 
NerMBRoTHA LIMACIFORMIS, sp. nov. 
Two specimens described by Mr. Crossland separately, but apparently 
referable to the same species. The notes on the living animals are as 
follows :— 
(1) “ Polycerid, on a piece of coral obtained by a diver from 1 fathom 
on a reef in the 8.E. part of Shab ul Shubuk. Strikingly long and narrow, 
measuring 20 mm. x 4 mm. when crawling. The head is rounded and about 
one millimetre wider. The foot isa mere groove. The body tapers to the 
sharply pointed tail, but is rounded in cross-section and has no processes 
whatever. Gulls short and thick, irregular in arrangement, so that it is not 
easy to say whether there are 3 or 4. They are very contractile but there is 
no gill-pocket. Rhinophores perfoliate, very long and carried vertically ; 
they have no proper pockets. Colour blood-red, with sparsely scattered 
small yellow dots and a few yellow blotches. Gills bright light yellow 
