The ultrastructure and innervation of the ear of the gar, Lepisosteus osseus

The endorgans of the inner ear of the gar were examined using transmission and scanning electron microscopy as well as nerve staining. The ultrastructure of the sensory hair cells and supporting cells of the gar ear are similar to cells in other bony fishes, whereas there are significant differences between the gar and other bony fishes in the orientations patterns of the sensory hair cells on the saccular and lagenar sensory epithelia. The saccular sensory epithelium has two regions, a main region and a secondary region ventral to the main region. The ciliary bundles on the main region are divided into two groups, one oriented dorsally and the other ventrally. Furthermore, as a result of curvature of the saccular sensory epithelium, the dorsal and ventral ciliary bundles on the rostral portion of the epithelium are rotated ninety degrees and are thus oriented on the animal's rostro-caudal axis. Hair cells on the secondary region are generally oriented ventrally. The lagenar epithelium has three groups of sensory hair cells. The groups on the rostral and caudal ends of the macula are oriented dorsally, whereas the middle group is oriented ventrally. Hair cell orientations on the utricular epithelium and macula neglecta are similar to those in other bony fishes. Nerve fiber diameters can be divided into three size classes, 1-8 microns, 9-13 microns, and 14 microns or more, with the smallest size class containing the majority of fibers. The distribution of the various classes of fiber diameters is not the same in nerve branches to each of the end organs. Similarly, the ratio of hair cells to axons differs in each end organ. The highest hair cell to axon ratio is in the utricle (23:1) and the smallest is in the macula neglecta (7:1). The number of sensory hair cells far exceed the number of eighth nerve axons in all sensory epithelia.     

Scanning electron microscopy of microcorrosion casts of the vascular bed in the skin of the spotted salamander,Salamandra salamandra L.

Microcorrosion casts of blood vessels in the skin of the spotted salamander, Salamandra salamandra L., were studied using scanning eletron microscopy. The investigated vessels include a subepidermal network of respiratory capillaries and the vessels of poison glands. A hypothesis is proposed, according to which both types of vascular beds possess a common origin. Probable factors involved in the differentiation of the primary netword of the subepidermal vessels in larvae are indicated and speculation concerning the supposed mosaic type of circulation in the capillaries of the subepidermal respiratory bed is presented.     

Scanning electron microscopy of the chick embryo

Internal anatomical features of developing chick embryos can be examined using the scanning electron microscope in embryos that have been sectioned at varying levels. Standard paraffin sectioning techniques are used. After removal of paraffin, embryos are dried by the critical point method and examined. The resulting scanning electron micrographs have proved to be exceptionally useful in teaching anatomy of embryos.     

Scanning electron microscopy of Penicillium conidia

The morphology of conidia in 211 species and 12 varieties belonging to the genus Penicillium Link ex Gray have been studied and compared.According to surface ornamentation, conidia have been classified into six groups: A, smooth-walled (7% of the species); B, delicately roughened (13%); C, warty (28%); D, echinate (10%); E, striate with low irregular ridges (36%); and F, striate with scarce high ridges or bars (6%). Whereas the first two groups are closely related in both shape and average size, a gradual reduction was observed in size and in the length/width (l/w) ratio in the remaining groups. Echinate conidia were globose, having the largest average size. Only four species produced conidia not surpassing 2 m in diameter. Maximum length observed was 8 m, and most elongated conidia had a l/w ratio of 3.5. Forty per cent of the species studied had globose conidia.Conidia of the monoverticillate species were generally smaller, more globose and frequently with ridges. In the Asymmetrica, the conidia were generally larger, and showed ridges in comparatively few species. Conidia of the Symmetrica, which were frequently striate with ridges, presented the most elongated forms. The largest average size was found in the conidia of the Polyverticillata which were generally warty. Finally, we have considered the variations in surface ornamentation of conidia during the evolution of the genus Penicillium and drawn attention to their possible relationship with certain habitats and ways of conidial dispersion.     

Scanning electron microscopy of experimental adiaspiromycosis

Adiaspiromycotic granulomas of mice experimentally inoculated with fungusEmmonsia crescens Emmons et Jellison 1960 were examined by scanning electron microscopy. Their morphology, surface structures, and germinating adiaspores isolated from granulomas are described.     

Scanning electron microscopy of vaginal colonization

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.     

Scanning electron microscopy of barley protoplasts

Summary Scanning electron micrographs of barley protoplasts were compared using various preparatory techniques. Numerous features were observed which turned out to be artifactual characteristics of the processing procedure used in collecting and dehydrating the samples. The most successful technique gave protoplasts which presumably maintained their natural structural integrity, as judged by retention of sphericity and absence of holes in the plasma membrane. The relative numbers of fragmented protoplasts and cellular organelles was also greatly reduced.