84 SCORPIONS 



in the Scorpionidae. In the first case the eggs pass quickly into the 

 oviduct and develop there, the embryos consuming the yolk with 

 which they are filled; in the second, the fertilised egg remains in 

 place and becomes closely commingled with the maternal tissues. 

 At the end of its development each embryo lies in a diverticulum 

 which possesses a tubular extension like an umbilical cord along 



, Vesicular organ 



ofchelicerae 



II embryo of embryo '®^^ Bottle 



Uterus 



Fig. 21. Developing embryos of scorpion (family Scorpionidae) 

 showing 'bottle and teat'. (After Vachon, 1953.) 



which pass nutrient fluids from the wall of the mother's intestine. 

 These are transformed by glandular secretions and then led through 

 the tube to the mouth of the embryo which has a well-developed 

 pharynx with which it sucks the maternal fluid (Vachon, 1950a). 

 The chelicerae of the embryo scorpion end in contractile vesicular 

 organs which actually take hold of the teat and carry it to the 

 mouth ! 



In many species the young are born during the night, some- 

 times in two batches separated by an interval of a day, but in 

 Buthotus alticola birth has been observed from 7.0 to 9.0 a.m. 

 (Serfat and Vachon, 1950). According to Fabre (1907) and Water- 

 man (1950) the young, which are born enveloped in their chorion, 

 are freed by their mother, but this unlikely hypothesis has been 

 disproved in B. occitanus, and in B. alticola by Serfat and Vachon 

 (1950) who state that the young free themselves without parental 

 assistance, while mEuscorpius flavicaudis the young escape by lacer- 

 ating the chorion with their stings (Cloudsley-Thompson, 1955a). 



The process of mounting the mother's back may take up to two 

 hours as the little scorpions are very plump and weak (Cloudsley- 

 Thompson, 1951; Schultze, 1927). Here they remain until after 

 their first moult. In P. longimanus this period lasts about ten days 



