Part 11. 
Review of the Literature. 
1 lie animals composing tlie modern family Onisciclae were classed by tlie early systematists 
with the Insects. Naturally it was not until their affinities with the Ci'ustacea were recognized 
tliat the question of their mode of respiration attracted attention. This relationship was established 
hy the labors of Cuvier and was first published in his Tableaux elementaires de This to ire 
naturelle des Animaux in 1798. The same author in his Histoire des progres des 
Sciences nature lies, records that Latreille was the first to fill the gap in Zoology due to a 
lack of knowledge of the mode of respiration in the Cloportides. He refers to an announcement 
made hy Latreille to the French Institute in 1814. 
“Er weisst an vieren der fraglichen Blatter einen kleinen gelhlichen Teil nach, welcher von 
einem Loch durchljohrt ist und in seinem Innern kleine Faden enthalt, welche er mit denen der 
Schnecke und des Scorpions vergleicht, denn of) sie gleich liei diesen anders angeordnet sind, so findet 
doch zwischen heiden, sowohl hinsichtlich der Struktiir als auch der Verrichtung, die grdsste Aehn- 
lichkeit statt. “ ^ 
To these observations Latreille later added another to the effect that the parts contain 
air. In his systematic treatise on the Crustacea, puldished in Regne Animal, first edition, 1817, 
describing tlie genus ArmacliUes he says : 
“Les ecailles branchiales et superieures du dessous de la queue out une rangee de petits 
troiis, donnant passage a l’air.“ 
Two years later Treviranus published a somewhat elaborate article on the anatomy and 
physiology of the terrestrial isopods. ^ He reached (juite different conclusions from those of Latreille 
to whose, work he makes no reference. He considered the first two pairs of appendages in Por- 
cellio to he wliolly concerned with the reproductive function. The openings associated with the cor- 
pora alba serve, he states, in the male for tlie discharge of the seminal ffuid and in the female 
for the admission of the male intromittent organ. He says : 
“Zwischen den heiden oheren Flatten an dersellien Stelle, wo bei dem Mannchen die Wurzel 
der Blithe liegt, befindet sich ohne Zweifel die aussere, zur Aufnahme des mannlichen Gliedes he- 
stimmte Oeffnung der weiblichen Zeugungsteile.“ 
After referring to the other pairs of plates, lying posteriorly to the two concerned in re- 
production, as similar but of simpler structure, he states that under these lie the organs of the 
‘ Translation of Dr. F. A. Wiese, Leipzig, 1829. 
^ Vermischte Seliriften, Grottingen, 1816, 
