2 12 
THE TANGANYIKA PROBLEM. 
about § length of head. Caudal rounded. Caudal peduncle deeper than long. 
3 22 — 23 
Scales 32-^ ; lat. 1 . Blackish brown, with scattered pale blue dots ; 
J jj ii — 12 6 — 9 r 
belly yellowish. 
Total length, 75 millim. 
Described from five specimens from Mbity Rocks and three from Kinyamkolo. 
The toothed portions of the premaxillary and mandible are much developed in 
depth, in a manner suggestive of the Sparida and Scarida , and the teeth are 
implanted in sockets. The deep triangular groove for the reception of the pra- 
maxillaries extends to between the orbits, and the occipital crest is prolonged to it ; 
the parietal crests are produced on the frontals ; the pneorbital is large, and the 
chain of suborbitals very slender. The pharyngeal teeth have long, slender shafts 
and conical brown cusps. The ribs are attached to the back of short transverse 
processes ; all but the last one support epipleurals ; the last four pracaudal vertebra 
have a hamal bridge. 
82. Spathodus erythrodon. — Blgr. 1900. 
83. Perissodus microlepis. — Blgr. 1898. (Fig. p. 213. Lower.) 
Ten teeth on each side of the pramaxillary, 9 on each side of the mandible. 
Depth of body 2§ times in total length, length of head 3). Snout a little longer than 
diameter of eye, which is 4 times in length of head, and almost equals interor- 
bital width ; lower jaw projecting ; maxillary extending to below anterior border of 
eye ; 3 series of scales on the cheek ; large scales on the opercle. Gill-rakers 
rather long, 14 on lower part of anterior arch. Dorsal XVIII. 10; spines increas- 
ing in length to the last, which measures 1 \ length of head; longest soft rays 
length of head. Pectoral £ length of head. Ventral not reaching vent. Anal 
III. 8; third spine longest, nearly as long as longest dorsal ; longest soft rays half 
length of head. Caudal truncate. Caudal peduncle i£as long as deep. Scales 
65 — ; lat. 1 ^ . Uniform dark reddish brown ; a blackish opercular spot. 
20 30 — 31 
Total length, 100 millim. 
Described from a single specimen from Mbity Rocks. 
84. Xenochromis hecqui. — Blgr. 1899. 
Three specimens from Usambura. Grows to a length of 270 millim. D. XVI.- 
XVII. io-ii ; A. III. 9-10; Sq. 64-67 — ; lat 1 
20 35—43 
85. Plecodus paradoxus. — Blgr. 1898. 
D. XIX. 14; Anal III. 12. Depth of body 4 limes in total length, length of 
head 4V times. Eye large, longer than snout, ^ length of head, i j interorbital 
width ; maxillary extending to below anterior third of eye ; 3 series of scales on 
the cheek. Sc. 6?. — ; lat. 1 
17 40 
Total length, 90 millim. 
