Part IL 

 Review of the Literature. 



1 lie animals composing tlie modern family Oiiiscidae were classed l)y the early systematists 

 with the Insects. Naturally it was not until their affinities with the Crustacea were recognized 

 that the question of their mode of respiration attracted attention. Tliis relationship was estaldished 

 l)y the labors of Cuvier and was first published in his Tableaux elementaires de l'histoire 

 naturelle des Animaux in 1798. The sanie author in his Histoire des progres des 

 Sciences naturelles, records that Latrkille was the first to fill the gap in Zoölogy due to a 

 lack of knowledge of the mode of respiration in the Cloportides. He refers to an annonncement 

 made hy Latkeille to the French Institute in 1814. 



"Er weisst an vieren der fraglichen Blätter einen kleinen gelblichen Teil nach, welcher von 

 einem Loch durchbohrt ist und in seinem Innern kleine Fäden enthält, welche er mit denen der 

 Schnecke und des Scorpions vergleicht, denn ol) sie gleich bei diesen anders angeordnet sind, so findet 

 doch zwischen beiden, sowohl hinsichtlich der Struktur als auch der Verrichtung, die grösste Aehn- 

 lichkeit statt." ^ 



To these obsei-vations Ija tkeille later added amither to the effect that tlie parts contain 

 air. In liis systematic treatise on the Crustacea, jjublished in Rt^-gne Animal, first edition, 1817, 

 describing the genus ArmadiUcs he says : 



"Les ecailles branchiales et superieures du dessous de la queue ont une rangee de petits 

 trous, dounant passage ä l'air.'- 



Two years later Treviranus published a somewhat ela})orate article on the anatomy and 

 pliysiology of the terrestrial isopods. ^ He reached (piite different conclusions from those of Latreille 

 to whose work he makes no reference. He considercd the first two pairs of appendages in For- 

 cellio to be whoUy concerned with the reproductive function. The openings associated with the Cor- 

 pora alba serve, he states, in the male for the discharge of tlie seminal fluid and in the femalc 

 for the admission of the male intromittent organ. He says: 



"Zwischen den beiden oberen Platten an dersellun Stelle, wo bei dem Männchen die Wurzel 

 der Kuthe liegt, befindet sich ohne Zweifel die äussere, zur Aufnalnne des männliclien Gliedes be- 

 stimmte Oefinung 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 ander these lie the organs of the 



' Translation of Dr. F. A. Wiese, Leipzig, 1829. 

 ^ Vermischte Schriften, Göttingen, löl6. 



