Flea Ctenophthalmus: Heterogeneous Hexagonally Organized Layer in the Midgut

Science  26 Apr 1968:
Vol. 160, Issue 3826, pp. 423-425
DOI: 10.1126/science.160.3826.423


The ventriculus or midgut of adult fleas of the genus Ctenophthalmus (Hystricopsyllidae) is surrounded by a complex investment consisting of a "beaded layer," circumferential and longitudinal muscles, minute fibrils of the sort commonly called collagenous, and a granular layer at the boundary of the hemocoel. The beaded layer is remarkable in consisting of two types of short cylinders of greatly different diameters, each type arranged in a mixed hexagonal array.