EEPORT ON THE AjVIPHIPODA. 273 



in the second tribe of the Amphipoda, which he calls Prostomatae, subsequently classing 

 them as the first family of his second division, Gammarina. He states that the large finger 

 of the first gnathopod is hinged, not as usually to the anterior, but to the lower hinder, 

 angle of the hand, and directed forwards. That this is not shown in Costa's figure may 

 have arisen from an accidental twisting of the hand in the specimen figured, or perhaps 

 the artist had the unwonted feature before him, but could not believe his own eyes, and 

 took the liberty of correcting nature, or we may argue from the researches mentioned below 

 that Costa's specimen had not reached the age at which the peculiarity is developed. Boeck 

 further differs from Hope by describing and figuring the third joint on the second peraeopod 

 as greatly expanded, by representing the first joint of the fifth perseopod in the complete 

 figure as drawn out on the lower hinder angle instead of rounded off, and by describing the 

 telson as split at the point, while in Hope's figure it is rounded and entire. But the figure 

 of the telson in Boeck shows no slit, and the downward produced angle of the first joint of 

 the perajopod is in the text and in a separate figure attributed to the fifth pair of feet, that 

 is, the third peraeopod, so that I am inclined to unite the two species in spite of differences 

 which seem to me more likely to be due to inadvertence in the observers than to diversity 

 in nature. This conclusion, independently arrived at, is more or less confirmed by the 

 recent investigations of Bovallius, who, in 188G, describes and figures with great clearness 

 and detail " the adult female " and " the young male " of Boeck's species, placing it in his 

 new tribe of Amphipoda Synopidea. He is evidently, like Boeck, unaware of Costa's 

 Guerinia, but he tlirows light upon it by showing that the position of tlie finger of the first 

 gnathopods is normal in young specimens, and that in these the third joint of the second 

 perseopod is not greatly expanded. On the other hand, he represents the telson as deeply 

 excavated in the young, but in the adult female as having a smoothly rounded termination, 

 " The description of Boeck," he says, " is not quite accurate ; it seems that he has taken 

 some characteristics from the adult animal and others from very young ones." 



The second species described and figured is " Callisoma Barthelemyi, Hope." The differences 

 mentioned, having to do, it seems, exclusively with comparative measurements, are probably 

 not of specific value. The name is not included in the Brit. Mus. Catal., and the species is 

 entered by J. V. Carus, 1885, as " non desoripta." The description is as follows: — " C. 

 antennis suporioribus capite thoracisque artioulo primo simul vix longioribus, seta primaria 

 pedunculo parum breviore, inferioribus thoracis articuli septimi $ , quinti ^ marginem 

 anticum attingentibus ; epimeris quarti paris postice tertium anticum marginis inferi sequen- 

 tium non ultra productis ; pedibus spuriis abdominalibus fere seque terminatis. Long. lin. 

 3; lat. lin. 1. " Osservazioni. Molto affine al Call. Hopei, A. Cost., dal quale nondimeno 

 differisce per la falsa unghietta de' piedi anteriori assai piii lunga, per le antenne in ambedue 

 i sessi rispettivamente piii corte, per gli epimeri del quarto anello un poco men prolongati 

 posteriormente." 



The third Crustacean of this paper is " J sera Hopeana" Costa, an Isopod. 



1853. Costa, Achille. 



Relazione sulla memoria del Dottor Achille Costa, di Ricerche su' Crostacei 

 Amjipodi del Regno di Napoli. Rendiconto della Society reale Borbonica. 

 Academia delle scienze. Nuova Serie. Anno 1853. Bimestre di Settembre ed 

 Ottobre. Napoli, 1853. pp. 166-178. 



The report on Costa's paper is dated Napoli, 17 Settembre 1853, and signed by Giovanni Gussone, 

 Giovanni Guarini, Benedetto Valpes. The characters of the new genera and species are 

 (ZOOL. CHALL. EXP. — PART L.xvii. — 1887.) Xxx 35 



