﻿BRITISH FOSSIL CRUSTACEA. 



ARRANGEMENT AND NOMENCLATURE OF THE SEGMENTS OR 



{According to the 





I. 



Segments of the Head (Edwards, 





I. s 



egments of theCephalothorax 







Bell, &c. &c.) 





(Dana)." 





I. 



1 . Bearing the Eyes. 



I, 



1. Ophthalmic Segment. 





II. 



2. „ „ Antennules, or Internal 

 Antennae. 



II. 



2. 1st Antennary „ 





III. 



3. ,, ,, External Antennae. 



III. 



3. 2nd „ 





IV. 



4. „ „ Mandibles. 



IV. 



4. Mandibular „ 



- 



V. 



5. „ „ 1st Maxillae. 



V. 



5.\ 







VI. 



6. ,, „ 2nd „ 



VI. 



6. 







VII. 



7. ,, „ Maxillipeds. 



VII. 



7. 







VIII. 



II. Segments of the Thorax. 

 1 . Bearing the 2nd Maxillipeds. 



VIII. 



8. 



5th to 14th Segments, Maxillary, 

 * and Podal, 10 pairs. 





IX. 



2. „ „ 3rd 



IX. 



9. 







X. 



3.' 





X. 



10. 







XL 



4. 



Either furnished with organs of 



XI. 



11. 







XII. 



5. y prehension or Ambulatory or 



XII. 



12. 







XIII. 



6. 



Natatory appendages. 



XIII. 



13. 







XIV. 



7. , 





XIV. 



14. J 









III. Abdomen. 





II. Abdomen. 





XV. 



M 



XV. 



15/ 







XVI. 



2. 





XVI. 



16. 







XVII. 

 XVIII. 



3. 

 4. 



Usually furnished with swimming 

 feet, or false abdominal feet ; 

 rudimentary in the Brachyura ; 

 branchiferous in Squilla ; ovige- 



XVII. 

 XVIII. 



17. 

 18. 



, 15th to 19th Segment, bearing 

 r abdominal feet. 





XIX. 



5. 



rous in the females of nearly all 



XIX. 



19., 











genera. 









XX. 



6;> 





XX. 



20. Segment, bearing caudal abdomi- 











nal appendages, 1 pair. 





XXI. 



7- Caudal segment destitute of appen- 



XXI. 



21st. Or caudal segment without ap- 







dages. 1 





pendages. 





1 Prof. Bell considers the extremely minute and moveable 

 points attached to the extremity of this segment in Palamon 

 serratus to be a pair of rudimentary appendages. — [See 

 Introduction to ' Bell's Hist. British Stalk-eyed Crustacea,' 

 p. xx, 1853.] 



2 "Crustacea have a cephalothorax, but not a head" — 

 Dana, on Homologies of Crustacea. — ' United States Explg. 

 Expedition,' Crustacea, vol. xiii. p. 21, 1852. 



