386 ARTHROPOD A. 



iferous genus is Belinurus, which agrees with the preceding 

 in having five thoracic and three abdominal segments, to- 

 gether with a long tail-spine, but in which the thoracic rings 

 are free and movable, while those of the abdomen are anchy- 

 losed with one another. According to the researches of Dr 

 Henry Woodward, it would also appear to be established 

 that the singular Crustacean fossils which have been grouped 

 together under the common title of Cydus (or Halicyne) 

 should be regarded as really larval forms of the Carbon- 

 iferous Limuloids Prestwichia and Belinurus. Leaving the 

 Carboniferous period, we find that Limuloid Crustaceans are 

 not unknown in the Permian and Triassic deposits, while 

 several species of a type apparently generically identical 

 with the recent Limulus occur in the Lithographic Slates 

 of Solenhofen (Upper Jurassic), and other forms have been 

 recognised in the Cretaceous and Tertiary. 



