No. 598] THE STERNUM IN SCORPIO! 



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Vejovis carol'uius is a small scorpion, its length not ex- 

 ceeding 34 mm. The width of the carapace at the pos- 

 terior edge is slightly less than the length. The center of 

 the eye tubercle is about ? of the entire length of the 

 carapace from its anterior edge. The sternum is pentag- 

 onal; the comb has 13-14 teeth; the central and inner 

 rows of plates in the comb are beadlike. The ringers are 

 rather short, being either as long as or only slightly longer 

 than the hand. 



Centrums 'nifnmatus is usually about 45 mm. long, but 

 large specimens measure up to 70 mm. The width of the 

 carapace at the posterior edge is equal to or even slightly 

 exceeds its length. The center of the eye tubercle is 

 abont | of the entire length of the carapace from its an- 

 terior edge. The sternum is triangular. The comb 

 usually has 18-19 teeth, although their number may reach 

 25. The central rows of plates is not beadlike, but com- 

 posed of five plates the limits between which are difficult 

 to ascertain. The inner row is beadlike. The fingers are 

 rather long, being more than 1 \ times as long as the hand. 



Let us now consider the Paheozoic scorpions. The 

 sternum of the Silurian Proscar pi us osborm Whitfield is 

 unfortunately not preserved. Its nearest European rela- 

 tive, the Silurian scorpion PaJa oplnnt us hutdrri Peach, 

 has, according to Pocock, a pentagonal sternum. The 

 sternum of the carboniferous >eorpion- i> fairly well. pre- 

 fers from all other fossil and recent scorpions in the posi- 

 tion of the fourth pair of coxa- which abut againsi the 

 genital opercula. The sternum is either triangular 

 {PaUeobuthus), rhomboidal (Isobuthus) or oval (Eobu- 

 thus). The family Cyclophthalmidie has a "pear-- 

 shaped sternum, the family Eoscorpionidie a distinctly 

 pentagonal one with parallel sides. If the pear-shaped 



shape to' pom- preservation or displacements, then these 

 types of sterna must have disappeared completely. a> has 



