The Occurrence of Situs inversus among artificially-reared Echinoid Larvae

CONTENTS. PAGE 1. I N T R O D U C T I O N . . . . . . . . . 105 2. D E S C R I P T I O N S OT T H E L A H V A E W I T H I N V E R S E S I T U S . . 1 0 7 3. R E S U L T S O F T H E E X P E R I M E N T S . . , . . . 1 1 3 4. C H A N G E S W H I C H M A Y P O S S I B L Y H A V E T A K E N P L A C E DURING* E A R L I E R S T A G E S . . . . . . . . 1 1 7 5. V A R I A T I O N S A M O N O D O U B L E H Y D R O C O E L E L A R V A E A N D O T H E R A B N O R M A L I T I E S . . 1 1 9 0. C O N S I D E R A T I O N S O N T H E O R G A N S A N D S T R U C T U R E S C O N C E R N E D A N D T H E F A C T O R S C O N C E R N E D I N T H E I R D E V E L O P M E N T . 128 7. P R O B A B L E M E C H A N I S M W H E R E B Y A B N O R M A L I T I E S A R E P R O D U C E D . . . . . . . . . . 139 8. E X T E R N A L F A C T O R S A S C A U S E S O F A B N O R M A L I T I E S . . . 143 9. S U M M A R Y A N D C O N C L U S I O N . . . . . . . 145 10. L I T E R A T U R E C I T E D . . . . . . . . 146 11 . A P P E N D I X . . . . . . . . . 148