CICHLID FISHES OF LAKE NYASSA. 687 



f. An opercular spot and a blaclcisli spot on or under lateral line below 



middle of spinous dorsal ; often a tliird spot below soft dorsal and a 

 fourtli at base of caudal J. 

 Of. 8 to 13 g-ill-rakers on lower part of anterior arcli (? H. iiiiermedius). 

 * Outer teeth bicirspid; lower jaw not projecting. 



Maxillarj- extending to below ej'e 18. « uritus. 



Maxillary not extending to below eye ; pharyngeal teeth 



small .'. 19. teti-astigma. 



Maxillary not extending to below eye ; pharyngeal teeth 



large, rounded, blunt 20. placodon. 



** Outer teeth conical ; lower jaw projecting (? S. intermecUus) . 

 Snout a little shorter than postorbital part of head ; last 



dorsal .spine nearly h length of head 21. iiitermedius. 



Snout as long as postorbital part of head ; last dorsal 



spine J, interorbital width ^ length of head 23. vwdestus. 



Snout as long as postorbital part of head ; last dorsal spine 



g- to f, interorbital width J or | length of head 23. icoodi. 



f3. 17 to 28 gill-rakers on lower part of anterior arch. 



17 to 21 gill-rakers ; 15 or 16 dorsal spines 24. chri/soiiofus. 



23 to 28 gill-rakers; 17 or 18 dorsal spines 25. quadrimaculatus. 



g. A dark band from nape or origin of dorsal to base of caudal (sometimes 



faint or absent in large specimens). 

 «. Lower pharyngeal with a group of large, rounded, blunt teeth. 



Jaws equal; caudal peduncle 1^ to Ij as long as deep 26. sphcerodon. 



Jaws equal; caudal peduncle If as long as deep 27. ericotmnia. 



Lower jaw projecting 28. later istriga. 



ji. Lower pharyngeal teeth of the 2 middle series a little enlarged. 



Eye 3 to 4 in head (in specimens of 70 to 110 mm.) 29. ]plagiot(Bnia. 



Eye 3 to 3§ in head (in specimens of 120 to 170 mui.) ... 30. melanotania. 



y. Pharyngeal teeth small ; outer teeth of jaws foraiing a close-set series, 

 usually bicuspid in young, some or all conical in adult. 

 * Lower jaw a little shorter than upper ... 31. guentheri. 



** Jaws equal ; 18 or 19 dorsal spines 32. melanonotus. 



*** Jaws equal or lower a little projecting ; 15 to 17 dorsal spines. 

 t Maxillary extending to vertical from anterior edge of eye. 



8 or 9 gill-rakers on lower part of anterior arch 33. hrevis. 



12 gill-rakers ; 35 or 36 scales ; caudal peduncle 1\ as long 



as deep 34. nototeenia. 



11 to 13 gill-rakers ; 37 to 39 scales ; caudal peduncle If 



to 2 as long as deep 35. lepturus. 



tf Maxillary not extending to below eye. 



Scales 35 to 37 ; last dorsal spine ^ to J head 36. rhoadesii. 



Scales 33 or 34 ; last dorsal spine quite f head 37. atritceniatus. 



S. Pharyngeal teeth slender; outer teeth of jaws conical, rather strong, 

 and sjDaced. 

 * Third anal spine as long as last dorsal ; pelvic fins shorter than 



head 38. spilorhr/nclnis. 



** Third anal spine shorter than last dorsal ; pelvic fins as long as 

 head. 

 Maxillarj" not quite reaching vertical from anterior edge 



of eye 39. longipes. 



Maxillarj^ not nearly reaching vertical- from anterior edge 



oi eye ' , 40. cceruleus. 



h. Coloration silver}', sometimes with faint dark cross-bars. 

 a. Maxillary extending to below anterior edge of eye. 

 Lower pharyngeal with a group of enlarged teeth with 



spherical crowns 41. macrocJdr. 



Posterior teeth of 2 middle series of lower pharyngeal 



somewhat enlarged , 42. argijrosoma. 



X I include H". modestus here, but its coloration is unknown ; the type, as 

 preserved, is uniformly brownish. 



