Scanning electron micrographs demonstrate the presence of microcrystalline structures on the surface of coal-derived fly ash samples taken from electrostatic precipitator hoppers. Cenospheres (hollow spheres) were found to be packed with smaller cenospheres, which were also packed with spheres. Microspheres, apparently formed by uneven heating, are encapsulated in the parent sphere. Chemical analyses provide a basis for the postulation of a mechanism of formation for plerospheres (hollow spheres packed with spheres) and microcrystals.

Cuticular markings of five species of Dirofilaria were examined by SEM. Variations in the patterns on the en face view were observed among the species. Transverse striations were observed on the cuticles of all five species, but longitudinal ridges were lacking on Dirofilaria immitis, the type species of the subgenus Dirofilaria. They were present on the other four species, Dirofilaria repens, Dirofilaria tenuis, Dirofilaria corynodes, and Dirofilaria magnilarvatum, members of the subgenus Nochtiella. Longitudinal ridges and other cuticular structures and patterns were seen to vary among the species and with the portion and aspect of the worm examined. It is suggested that SEM would be a good tool for a detailed study of specific cuticular morphology of all species of Dirofilaria, thus contributing toward their differentiation and recognition.

Cryptosporidia are coccidian parasites of the suborder Eimeriorina. They have been found inhabiting the mucosa of the stomach, small and large intestine, gall bladder and bile ducts, pancreatic ducts and respiratory tract of a wide variety of animal species. A clinical syndrome of watery diarrhea, often severe and sometimes fatal, has been reported in guinea pigs, (bovine) calves, pigs, Arabian foals, rhesus macaques, and man.'-'The cases reported here are from three species of macaques-two Macaca mulatta (I and 11), and one each M. radiata (111) and 1M. fascicularis (IV). All were born and maintained at the California Primate Research Center. All were juveniles, ranging from three to ten months of age at necropsy. Monkeys I, 111, and IV had been housed at some time in the colony nursery-two concurrently (111 and IV). Monkey I1 was housed in an outdoor field cage and died after 12 hours hospitalization. Monkeys I and I11 became ill within one week of weaning; monkey IV was a small weak baby and was hand reared with onset of diarrhea at one week of age. Onset of diarrhea was not noted in monkey 11. Clinical signs generally were limited to depression, dehydration, weight loss, and diarrhea which persisted despite fluid and nutritional therapy in monkey I and, in addition, oral antibiotic therapy in the other three macaques. All had fecal cultures at weaning, during their illness, and at necropsy which were negative on selective media for Salmonella, Shigella, and Yersinia spp. Examination for fecal parasites by fecal smear also was negative during the clinical illness of all but monkey I1 in which a few Trichomonas sp and rare Chilomastix sp were reported.All had complete blood counts (red blood cells, white blood cells, and differential) at weaning which were within normal limits for this colony. Monkeys I and I1 died despite intensive fluid therapy. Monkeys I11 and IV were killed painlessly due to continued loss of condition despite therapy.At necropsy all four macaques were underweight for age and dehydrated with dried fecal material staining the perianal region. The intestines were distended variably with fluid and gas, and the content remained liquid throughout the tract. Grossly, the mucosa of the small intestine was normal. In three of the macaques enlargement of the mesenteric lymph node was noted-up to double normal size. Monkeys I and 111 lacked a visible thymus; a few lobules of white tissue were found in the mediastinum but the total weight was less than a gram. These same macaques had consolidated, hemorrhagic lung lobes.Histologically, the lesions seen in the small intestine were mild to moderate blunting and fusion of villi, variation in height of enterocytes, necrosis of individual enterocytes, and increased numbers of mitotic figures in crypts. There were variable numbers of round, irregularly sized, lightly basophilic, bodies ( 1 to 4 pm) adherent to enterocytes along the tips and side of villi as well as within the crypts where they sometimes were accompanied by cellular debris ( fig. 1). Many e...

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