141 



On the Development of Palinurus vulgaris, the Rock 

 Lobster or Sea Crayfish. 



By 

 J. T. Cuuuiugham, 9I.A. 



With Plates VIII and IX. 



1. Historical Review. 



The history of our knowledge of this subject is complicated and 

 curious, and is not quite correctl}^ narrated in any English publica- 

 tion^ not even by Balfour in his account of the development of 

 Crustacea (Comparative Embryology, vol. i). The story begins 

 with the establishment and definition of the genus Phyllosoma by 

 Leach in 1818. Various succeeding zoologists included descriptions 

 of species of Phyllosoma in their works, but the result of all previous 

 investigations are included by Milne Edwards in the comprehensive 

 account of the genus given in his Hist. Nat. des Crustaces, vol. ii, 

 1837. The state of knowledge at that time may be briefly summa- 

 I'ised as follows : — The Crustaceans known by the name Phyllosoma 

 had been found near the surface of the ocean in various parts of 

 the "world. They varied in size from less than half an inch to two 

 inches. They were, when alive, of glassy transparency ; the body 

 was remarkably flat, and expanded horizontally, while the limbs 

 were long, slender, and biramous. The body consisted of three parts ; 

 firstly, a head having the form of an oval leaf, bearing at its ante- 

 rior extremity a pair of eyes on long stalks and two pairs of simple 

 antennae. The mouth was situated beneath the middle or posterior 

 third of the head, and surrounded by an upper and lower lip, a pair 

 of mandibles, and the first pair of maxillse. The second pair of 

 maxillae and the first pair of maxillipeds were rudimentary and 



