DEVELOPMENT OF PALINUEUS VULGARIS. 145 



full account of tlie metamorplioses of Palinurus, an object which 

 has never yet been realised either by Gerbe or anyone else. 



In 1863 Glaus, in an account of observations made at Messina 

 (Zeit. f. wiss. ZooL), described the embryo of Palinurus before 

 hatching, and compared it with young Phyllosomata captured in 

 the sea. He found differences in this comparison which appeared 

 to him inexplicable on the view that Phyllosoma was the larva of 

 the Palinuridx. Spence Bate also came forward to oppose the 

 correctness of the conclusions of Couch and Gerbe, in a paper in the 

 Ann. and Mag. Nat. Hist., ser. 4, vol. ii. 



Dohrn, however, in J 870 (Zeit. f. wiss. Zool.) published an im- 

 portant confirmation of the identity suggested by Couch and Gerbe. 

 He gives a description of the development of Scyllarus in the egg, 

 and of the newly hatched larva, which he shows to be identical 

 with the smallest Phyllosoma obtained by Glaus from the sea. He 

 shows that the second maxilla gets smaller during the end of the 

 embryonic period, while the first maxilliped disappears altogether 

 before hatching. The second antenna is much shorter than the first. 



In the embryo of Palinurus, at an early stage, the second antenna 

 is longer than the first ; the second maxilla is biramous, the inner 

 branch smaller than the outer. The first maxilliped is at first 

 distinctly biramous, but the branching disappears ; the appendage 

 becomes simple, but does not disappear as in Scyllarus. The abdo- 

 men is rounded at the end^ and the last pair of appendages is indi- 

 cated. In the embryo, when ready to hatch, Dohrn states that the 

 first maxilliped is quite short and thick, and appears to have a pro- 

 minence near the base, which probably developes later into a bran- 

 chial plate. Dohrn gives no figure nor further description of the 

 hatched larva. 



In 1873 Ferd. Eichters published in the same Zeitschrift a paper 

 containing the results of a critical examination of a large collection 

 of specimens of Phyllosoma from the Hamburg Museum. Richters 

 has shown by tracing successive stages in his specimens, and com- 

 paring them with the observations of Glaus and Dohrn, that all 

 those Phyllosoraes which possess the following three characters 

 belong to the genus Palinurus, which is distinguished from the other 

 genera of its family, such as Scyllarus, by having long, cylindrical, 

 multiarticulate second antennae, whereas the others have short, 

 flat, broad second antennae with few segments. The three distin- 

 guishing characters of the Palinurus Phyllosomes are — 



(1) The second antennas are longer than the first in the earliest 

 stages, and later on always remain cylindrical ; while in the Scyllarus 

 Phyllosomes the second antennge are in the earliest stages much 

 shorter than the first, and soon become broad and flat. 



