88 THE VOYAGE OF H.M.S. CHALLENGER. 



these animals is sufficient to warrant us in stating that all Phyllosomas are the young 

 of Polinurus, or some allied genus ; if so, it is certainly remarkable that the brephalos 

 undergoes no change while it continues to grow from the tenth of an inch to an inch in 

 length, and that it then should undergo an immediate alteration, changing from a thin, 

 translucent animal, to one thick, solid, and perfectly robust. 



Synaxes, Spence Bate. 

 Synaxes, Spence Bate, Ann. and Mag. Nat. Hist., ser. 5, vol. vii. p. 220. 

 This genus consists of those species in which the rostrum is produced anteriorly beyond 

 the extremity of the somite that carries the first pair of antennas, and unites with that of the 



Fio. 11.— Dorsal view of Synaxes. Fig. 12.— Lateral view of Synaxes. 



second pair of antennas so as to make a perfect orbit, and covers the ophthalmic somite 

 as shown in the annexed woodcuts. The first pair of antennae carries two short flagella, 



Synaxes hybridica, Spence Bate. 



Synaxes hybridica, Sp. B., loc. cit, p. 220, pi. xiv. figs. 1-6. 



No specimen in the Challenger collection. 

 Habitat. — West Indies. 



Observations. — Palinurellus, v. Martens, according to that author differs from Synaxes 

 in having the posterior pair of pereiopoda chelate in the female, and Boas in his Studier 

 over Decapodernes Slsegtskabsforkold, p. 183, considers it as the most primitive form of 

 the Palinuridse, and therefore nearer Homarus. 1 



Palinurellus gundulachi, Martens, was taken off Cuba. 



Avseostemus, De Man, Professor Martens 2 considers to be the same as Palinurellus. 



Arseosternus wieneckii, De Man, was taken off Sumatra. 



Geological Range. — The genus Palinurina was established by Munster for species 



1 K. Dansh. Vidensk. Selsk. Skr., Ek. 6, Bd. i., 1880 ; Zool. Record, 1881, Crust, p. 20. 

 - Zool. Record, 1881, Crust, p. 20. 



