ARTICLE XV. 



On the Organization of the Genus Gregarina of Dufour. By Joseph Leidy, M. D. Read 



January 3, 1851. 



In 182G, Dufour described in the Annates des Sciences NatUrelles, an cntozoic parasite 

 found within the intestinal canal of various coleopterous insects. He gave a general 

 account of its structure, and notices its apparent analogy to the genus of intestinal worms, 

 Caryophylleus, of Rudolpbi, and also remarks, p. 45, that Ramdohr has represented the 

 same animal under the name of "Petit sac dc 1'EpipIoon," found in the Dermestes lardarius. 



In 1828, Dufour, in the same work, characterized the parasite as a new and distinct 

 genus of entozoa, under the name of Gregarina, "que cxprime l'habitude qu' ont ccs vers 

 intestinaux de vivre en troupeaux." Those infesting Coleoptera, he designated under the 

 general specific name of Gregarina conica, those found in the Forficula, he called Grega- 

 rina ovata. The author gives three figures of the latter, one of which represents an 

 attached pair. 



In 183S, Ilammcrschmidt indicated, in the Isis von O/cen, a number of species of Gre- 

 garina, which, with very little reason, he subdivided into five genera. 



Siebold, in 1829, Kollikcr, in 1815, Ilenle, in the same year, Frnntzius, in 181G, and 

 Stein, in l^K wrote upon the character of the Gregarina;; but to their writings I have 

 not been able to have access. 



In 1818, Iiiolliker wrote a second time on the nature of Gregarina, in Siebold and Kdl- 

 liker's Zeitschrift fur Wissenschaftliche Zoologie,vsA. i., p. 1, in which he contends that 

 this singular helminth is a single, simple- organic cell, — an opinion he held in his former 

 memoir, and which, according to this author, was questioned by Ilenle and I'rant/.ius. 



In the second part of the latter memoir of Kollikcr, p. 18, on the general views of the 

 nature of Gregarina, he asks "Sind de Gregarinen Thicre?" (arc the Gregarina animals?) 

 a question which arose from an opinion expressed by Ilenle, from their relationship to the 

 receptacles of the navicella, which latter arc usually considered as vegetable in their 

 nature. In answer to the question, the author says, the contractility of the membrane 

 and its solubility in acetic acid, speak pretty safely for the animal nature of the Gregarina, 

 as no contractile cell membrane soluble in acetic acid is yet known among plan 



• Loc. cit. p. 18. 'Die Contractilitat der Membran derselben iind zweitens deren AuflOslichkeil in Gssigsaare 

 ziemlich sicher far die thierische Natnr dieser Wesi ben, da man bis jezl bei Pflanzen dnrohaua keine con- 



tractile und in 1 iche Zellmembranen kennl 



