376 PROF. E. R. LANKESTER ON CERTAIN POINTS IN THE 
The system is an absolute failure. The number and size of the lateral eyes is not 
even constant in the same individual (the two sides differing sometimes); much less is 
it so in species and still less in genera. The only generalization which can be made 
about the lateral eyes, is that in the Scorpions with triangular sternum, they are 
usually more numerous than in those with pentagonal sternum; but not even in 
reference to such large sections can a strictly accurate statement of the kind be made. 
Peters made a great advance in recognizing the form of the sternum (or metasternite, 
the equivalent of the chilaria of Limulus) as a basis for a primary division of the 
Scorpions. He combined with the consideration of this character a reference to the 
dentition of the chelicere ; and thus was led to establish four groups or subfamilies of 
the family Scorpionide (the Linnean genus Scorpio), viz. :— 
Group I. TELEGONINI. 
Sternum linear; two or three lateral eyes; both the fixed and the movable joint of 
the chelicera have a single row of teeth. 
Genera :—Telegonus, Koch; Cercophonius, Peters; Acanthochirus, Peters; Bothri- 
urus, Peters. 
Group II. ScorpPionin1. 
Sternum quadrate or pentagonal; both the fixed and the movable joint of the cheli- 
cera have a single row of teeth. 
Genera :—Vejovis, Koch ; Brotheas, Koch; Scorpio, Linné in part (= Scorpius, Ehr.) ; 
Scorpiops, Peters ; Urodacus, Peters; Hemiscorpion, Peters ; Ischnius (Sisyphus, Koch), 
Gervais; Opisthacanthus, Peters; Dacurus, Peters; Opisthophthalmus (Atreus), Koch ; 
Heterometrus, Ehr. (=Buthus in part, Ehr., not Leach); Diplocentrus, Peters. 
Group III. Centrurini. 
Sternum triangular; movable ramus of chelicera with fwo rows of teeth, the fixed 
ramus with one row. Hands of the chele spindle-shaped. Often a spine beneath the 
sting. 
Genera :—Centrurus, Ehr. (not Koch, =Zithyus of Koch, Atreus of Gervais, not 
Koch); Uroplectes, Peters. 
Group IV. AnpDRocronInI. 
Sternum triangular; both rami of the chelicera with two rows of teeth. No spine 
beneath the sting. 
Genera :—Prionurus, Ehr. ; Buthus, Leach. 
