G. Thomas et W. Bockeler, INVESTIGATION OF THE INTESTINAL SPHEROCRYSTALS OF DIFFERENT CEPHALOHAENIDA (PENTASTOMIDA), Parasitology research, 80(5), 1994, pp. 420-425
The midgut cells of cephalobaenid pentastomids contain spherocrystals
varying in size and appearance between the genera. Iron was detected i
n the vicinity of the crystals in all three genera, being considerably
fainter in Reighardia sternae than in the other species. Ultrastructu
rally a distinct lamination of the spherocrystals was evident, being f
aint in R. sternae but clearly expressed in Raillietiella hemidactyli
and Cephalobaena tetrapoda. According to the species, their diameter r
anged from 1.3 to 6.25 mu m. The size and number of the crystals were
highest in R. hemidactyli and lowest in R. sternae. The inclusions wer
e formed in the endoplasmic reticulum and migrated toward the cellular
apex, accumulating there and being expelled into the midgut lumen. As
determined by energy-dispersive X-ray analysis, calcium turned out to
be the main component of the crystals. Furthermore, small amounts of
chlorine and iron could be traced in the crystals. The relevance of th
e crystals is regarded as a kind of storage excretion such as that pre
sent in many other arthropods.