Classijicatwn of Scarpions. S 



of Peters distinguishes itself before all previous attempts, iu 

 that he has called attention to characteristics, overlooked by 

 all his predecessors, which have the advantage of being emi- 

 nently constant and trustworthy. It is especially the form 

 of the sternum and the different tooth armature of the man- 

 dibles that aftbrd the distinctive characteristics of the four 

 " groups " into which Peters arranges the scorpions. In his 

 first group, Telegonini, the sternum is extremely short, trans- 

 verse, almost forming a mere line, and both lingers of the 

 mandibles are armed with a single row of teeth. In the second 

 group, Scorpionini^ the sternum is large, almost pentagonal, 

 with parallel lateral margins, and the mandibles are similar to 

 those of the preceding group. In the third group, Centrurint, 

 the sternum is small, triangular, narrowing in front, and the 

 movable finger of the mandible armed with two, the im- 

 movable Avith one row of teeth. Lastly, in the fourth group, 

 Androctoninij the sternum has the same form as in the Cen- 

 trurinij but both fingers of the mandibles are provided with, 

 two rows of teeth. These four groups are further divided into 

 several (in great part new) genera, distinguished by difi:er- 

 ences in the form of the cephalothorax and the tail, the arma- 

 ture and sculpture of the latter, the number and position of 

 the eyes, the form of the hands, &c. With regard to the 

 lateral eyes, a distinction is made between the usually larger 

 and in number and position almost uniformly constant " prin- 

 cipal " lateral eyes and the more variable " accessory" eyes. 



The modifications of Peters's system which I have thought 

 proper to adopt are not of any especially great consequence. 

 I have, however, found that similitude in the form of the 

 sternum is not accompanied by similitude in the dental arma- 

 ture of the mandibles quite so often as Peters supposes ; and I 

 cannot, therefore, attribute to the characteristics derived from 

 the mandibles the same importance that he does. One conse- 

 quence of this is, that I find myself led to combine Centrurini 

 and Androctonini in one and the same principal group. 

 Moreover I think I have found in the form of the ijectoral 

 combs two separate types, which in a systematic point of view 

 are probably quite as important as the different forms under 

 which the sternum presents itself. The " combs " are, as is 

 known, a sort of oblong laminse, each made up of more or less 

 numerous longitudinally arranged lamellEC, and bearing in its 

 posterior margin a row of long, narrow, closely set parallel 

 processes, the so-called teeth of the comb. The first (front) row 

 of lamella is composed oi three large plates, which may be called 

 lamellce dorsuales ; the hindmost row consists of a number of 

 very small rounded lamellte, one behind the base of each tooth 



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