PSEUDO-SCORPIONIDA. 



835 



The heart consists of a dorsally placed tube, the number of 

 ostia which open into it is still a matter of dispute ; possibly 

 it varies in different species. 



The nervous system in the young is discrete, as many as 

 sixteen ganglia being distinct, but in the adult these have fused 

 into a common mass. 



The ovary is median and has projections which contain the 

 maturing ova. Laterally and anteriorly it is continuous with the 

 right and left oviducts which form the typical arachnid ring 

 uniting ventrally at the genital orifice. The testes form a net- 

 work arrangement (a development of the ring), which communi- 

 cates with a right and left vas deferens. A pair of accessory 

 glands discharge their 

 contents close to the 

 external orifice. Two 

 peculiar eversible struc- 

 tures are found in this 

 region in the male. They 

 are termed "ram's 

 horns " and are by some 

 authorities thought to 

 have to do with the copu- 

 lation. The eggs are 

 carried about by the 

 mother attached by some 

 secretion to the ventral 

 surface of the abdomen. 

 The silk glands produce 

 the silk for a w^eb or nest 

 in which the female retreats whilst the eggs mature. 



The Chernetidia are carnivorous, feeding mainly on small 

 insects or unresisting larvae. They are retiring in disposition 

 and live for the most part under leaves, stones, bark and moss. 

 They can as a rule run swiftly forwards, backwards, and sideways, 

 and usually w r ave their large pedipalps in the air. Although 

 seldom seen they are widely distributed, and this may partly 

 be due to their habit of clinging with their pedipalps to flies 

 and locusts and other insects which transport them in their 

 flight. Various extant forms, such as Chelifer and Chernes are 

 found in the Oligocene amber. 



FIG. 548. Chelifer sesamoides, Savigny. a Thorax 

 (prosoma) ; b abdomen ; c chelicerae ; d eyes ; 

 e hinder segment of thorax ; / front segment of 

 thorax ;j h pedipalpi. 



