CONTENTS. 



Page 



I. Introduction 7 



II. Historical 8 



1 1 T. A status leniusculua 



1. Introduction 9 



3. Source of material 9 



3. Care, food, habits, etc., of adults 10 



4. Breeding 11 



5. Development of eggs 12 



G. Hatching 14 



7. First larval stage: Sine; habits; appendages; relation to mother; telson 



thread 16 



8. Second larval stage: Size; habits; appendages 27 



9. Third larval stage : Size; habits ; appendages 34 



10. Fourth larval stage and later stages : Rate of growth 38 



11. Comparisons with European Astacus 40 



12. Bearing of artificial breeding upon possible acclimatization and economic 



problems and upon geographical distribution 41 



I V. Cambarus affinis 41 



1. Introduction ; resume of breeding habits 41 



2. Maternal structure for attachment of young 42 



3. Hatching 43 



4. First larval stage: Size; appendages; habits; relation to mother; telson 



thread 43 



5. Second larval stage: Size; appendages; habits; relation to mother, anal 



thread 50 



6. Third larval stage : Size ; habits ; tropisms 57 



7. Fourth and later larval stages : Number of moults and rates of growth ... 63 



8. Ratio of sexes ; sexual maturity 67 



V. Comparisons and conclusions 69 



5 



