SITUS INVERSUS IN ECHINOIDS 



109 



Text-fig. 1. 



St 



sp, 



Full-grown larva of Echinus miliaris with inverse situs. 

 Ventral view. x75. 



an, anus ; cd, constriction between larval oesophagus and stomach ; 

 ep, ventral and dorsal epaulettes ; mo, larval mouth ; p.y. constric- 

 tion between larval stomach and intestine ; rd, echinus-rudiment 

 formed on the right side ; sp^, rudiment of posterior unpaireti 

 spine situated a little on the left to the median line ; sp^, a pair 

 of groups of spines formed on the left side. 



I2 



