158 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
SMITTIA EGYPTIACA, var. HEROOPOLITA, nov. (Plate 15. figs. 7, 8.) 
This has the zocecia in a double row as in the type, and has the chitinous 
ridge on the operculum as in S. egyptiaca, novy., but the zocecia are small, 
the side of the aperture is more raised, and there are larger avicularia at the 
border of the ovicell and elsewhere. The specimens have ovicells to almost. 
all the zocecia. 
Loc. From buoy at the entrance of the Canal at Suez (14), collected by 
Crossland. 
RuyNncHozoon corruGcatum (Thornely). (Plate 12. figs. 14-16.) 
Rhyncopora corrugata, Thornely, ‘‘ Manaar,” p. 118, fig. 5. 
Zoarium adnate. Zocecia lageniform, with large raised peristome, more 
elevated at the sides than elsewhere, and within it a small circular avicu-. 
larium which, in dried specimens, sometimes looks like an irregular denticle.. 
The surface of the zoarium is frequently covered with large nodules. The 
ovicell is recumbent, rather straight at the sides, with a large circular area at 
each side. The oral aperture is nearly round, with a wide “ poster,” and 
the operculum, which is of the Lagenipora type, has the muscular dots some: 
distance from the border. 
An imperfect dry specimen from a buoy at Suez was not understood 
until an undetermined specimen in better preservation from Suez Bay was 
found in the British Museum (Busk collection). After these specimens had 
been studied and figured, Miss Thornely kindly showed me her Manaar 
collection, and assisted me in the examination of the Liverpool University 
collection. 
The nodules on the Manaar specimens are not so pronounced as those from 
the Red Sea, in fact are sometimes absent. The peristome is, however, 
raised in the same way, and there is sometimes an avicularium within the 
peristome ; the denticle may then be the end of the avicularian chamber; 
and in the Manaar specimen, even when no avicularium is visible, there is 
sometimes a tube by the wall of the peristome, as if leading to an avicularian 
chamber. 
The zocecia of specimens from the buoy are larger than those in the 
British Museum, and from the variation in the secondary aperture I have 
a suspicion that R. corrugatum and R. incisor, Thornely, may be found 
to be the same species. I did not see any &. incisor in Liverpool with 
ovicells. 
Loc. Gulf of Manaar (Thornely); buoy at the entrance of the Suez 
Canal (14), Crossland collection ; Suez Bay (Busk coll.), British Museum,’ 
99.7.1.2012. 
