192 PROF. J. D. F. GILCHRIST ON A 



(2) Carapace and Telson. 



The carapace, with special reference to the arrangement of spines, has 

 been described by Bouvier (2) in 19 12, and Archey (1) in 1915. Bouvier's 

 specimens were described by Grruvel (6, 7) as the young of Jasus lalandii, 

 from three examples procured from the Island of St. Paul. Bouvier agrees 

 that the puerulus is to be referred to this species, both from the fact that this 

 is the only palinurid found on the island, and from his examination of the 

 specimens. 



The arrangement of the spines of the carapace he describes as follows : 

 " Outre les deux paires d'epines frontales caracteristiques des puerulus, la 

 carapace presente une epine gastrique et, de chaque cote, deux epines 

 branchiales anterieures, l'une a l'extremite meme de l'arete dorso-laterale, 

 l'autre situee un peu plus en arriere et au voisinage de la region gastrique. 

 On observe a l'etat de rudiments une paire d'epines gastriques posterieures, 

 deux paires successives d'epines cardiaques, et un rangee d'epines marginalea 

 posterieures." 



Archey's specimens were from Stewart Island, New Zealand, and he 

 describes the spinulation of the carapace as follows : — " Supra-orbitals large, 

 projecting upwards and outwards, with a very small spine immediately at 

 their bases; post-orbital smaller than supra-orbital and each with a still 

 smaller spine behind." Further details are indicated in his figure, which 

 shows two small spines at the base of the median gastric, and three pairs of 

 cardiac spines, that is, more spines than in Bouvier's specimen. He states 

 that the spines though few are distinct, while Bouvier found that the 

 posterior gastrics and the cardiac, as well as the marginal spines, were rudi- 

 mentary and were much in the form of " saillies obtuses tres peu visibles." 



In the Cape specimen (5) no spines were found alongside of the median 

 gastric, no pair of posterior gastrics, and only one pair of cardiacs, while 

 the row of marginal spines, found both by Bouvier and Archey were not 

 seen. 



All these accounts therefore, of the number and arrangement of the 

 spines, differ from each other, and it would appear either that there may be 

 a variation in the species in the widely separated localities from which the 

 specimens were procured, or that, if a larger number of specimens had been 

 available for examination, individuals would have been found to vary con- 

 siderably. The question as to whether or not the puerulus, as well as the 

 succeeding stages, are characterised by the possession of a definite number 

 and arrangement of spines is an important one in any attempt to follow out 

 the life-history of the animal in detail, and, with a view to throw some light 

 on this point and the apparent discrepancy in the descriptions, all the Cape 

 pueruli procured (about 30) were re-examined. It was found that, while all 

 of them had the thirteen spines which I originally described (5), a good 



