152 Ona new Cichlid fish from Lake Tanganyika. 
XX.—A new Cichlid Fish of the Genus Limnochromis 
from Lake Tanganyika. By C,. Tate Reaan, M.A.,, F.R.S. 
(Published by permission of the Trustees of the British Museum.) 
Limnochromis otostigma, sp. n. 
Pelmatochromis auritus (part.), Bouleng. Cat. Afr. Fish, iii, p. 415 
(1915). 
Depth of body 3 to 34 in the length, length of head 3 to 34. 
Snout as long as or shorter than diameter of eye, which is 3 
to 34 in length of head, greater than preorbital depth ; inter- 
orbital width 4 to 44 in length of head. Jaws equal ante- 
riorly ; maxillary extending nearly to below middle of eye; 
teeth small, in 2 or 3 series. 4 or 5 series of scales on cheek. 
11 or 12 gill-rakers on lower part of anterior arch. A more 
or less distinct papillose pad on each side in front of the 
upper pharyngeals. Lower pharyngeal a triangular plate 
with doubly convex posterior edge and with a long anterior 
blade; teeth all slender. Dorsal XV (XVI) 9-10; last 
spine 3 length of head. Anal II{ 8-9. Pectoral as long as 
head, extending to origin of anal. Caudal rounded. Caudal 
peduncle 14 as long as deep. 395 or 36 scales in a longitu- 
dinal series, 5 or 6 from first dorsal spine to lateral line. 
Olive-brown, with oblique cross-bars of silvery white; a 
blue-black opercular spot ; fins greyish. 
‘Lake Tanganyika. 
Seven specimens, measuring up to 100 mm. in total length. 
L. auritus is often a little deeper (depth 24 to 3 in the 
length) and has the mouth a little smaller (maxillary to below 
anterior 1 of eye), and the spinous dorsal, with 16 or 17 spines, 
a little lower ; also the silvery-white cross-bars on the body 
are absent, but the vertical fins have pale spots and dark 
stripes. The most notable external difference between the 
two species is in the form of the caudal fin, rounded in 
L. otostigma and emarginate in L. auritus ; this is not due to 
age, but is evident when examples of the same size are com- 
pared. Another important difference is that in L, auritus 
the lower pharyngeal has no distinct anterior blade and that 
a few teeth in the middle near its posterior edge are rather 
stout and blunt. 
