For the first time, the histomorphology of the penis bone of a bat (Plecotus austriacus) was examined in detail. From Plecotus austriacus, 14 whole penes and 11 isolated bacula were studied and compared to bacula of Plecotus auritus and Plecotus macrobullaris. The baculum was located on specimen microradiographs and in micro-CT images in the tip of the penis. Using serial semithin sections and surface-stained, undecalcified ground sections, the types of bone and other tissues constituting the baculum were examined by light microscopy. 3D reconstructions were generated from the serial semithin sections and from micro-CT images. The shaft and the proximal branches of the Y-shaped baculum form a tubular bone around a medullary cavity. Since the small diameter of this channel and the main lamellar bone around it resemble a Haversian canal, the baculum is equivalent to a single-osteon bone. Several oblique nutrient canals enter this medullary cavity in the shaft and branches. All ends of the baculum consist predominantly of woven bone. The collagen fiber bundles of the tunica albuginea of both corpora cavernosa insert via fibrocartilage into the woven bone of the branches. Thus, the microscopic structures support the hypothesis that the baculum functions as a stiffening element in the erect penis. In this study, several microscopic imaging techniques were evaluated for displaying the microscopic structures of the baculum. Specimen microradiography, but especially micro-CT proved to be suitable nondestructive methods for accurate and reproducible demonstration and comparison of the three-dimensional structures of the baculum in different bat species. Anat Rec, 293:1248Rec, 293: -1258

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Detailed knowledge of histomorphology is a prerequisite for the understanding of function, variation, and development. In bats, as in other mammals, penis and baculum morphology are important in species discrimination and phylogenetic studies. In this study, nondestructive 3D-microtomographic (microCT, µCT) images of bacula and iodine-stained penes of Pipistrellus pipistrellus were correlated with light microscopic images from undecalcified surface-stained ground sections of three of these penes of P. pipistrellus (1 juvenile). The results were then compared with µCT-images of bacula of P. pygmaeus, P. hanaki, and P. nathusii. The Y-shaped baculum in all studied Pipistrellus species has a proximal base with two club-shaped branches, a long slender shaft, and a forked distal tip. The branches contain a medullary cavity of variable size, which tapers into a central canal of variable length in the proximal baculum shaft. Both are surrounded by a lamellar and a woven bone layer and contain fatty marrow and blood vessels. The distal shaft consists of woven bone only, without a vascular canal. The proximal ends of the branches are connected with the tunica albuginea of the corpora cavernosa via entheses. In the penis shaft, the corpus spongiosum-surrounded urethra lies in a ventral grove of the corpora cavernosa, and continues in the glans under the baculum. The glans penis predominantly comprises an enlarged corpus spongiosum, which surrounds urethra and baculum. In the 12 studied juvenile and subadult P. pipistrellus specimens the proximal branches of the baculum were shorter and without marrow cavity, while shaft and distal tip appeared already fully developed. The present combination with light microscopic images from one species enabled a more reliable interpretation of histomorphological structures in the µCT-images from all four Pipistrellus species.

Background: Turtles are adapted to different environments , such as freshwater, marine, and terrestrial habitats. Examination of histological and ultrastructural features of the dorsal lingual epithe-lium of the red-eared turtle, Trachemys scripta elegans, and comparison of the results with those of other turtles should elucidate the relationship between the morphology of tongues as well as the fine structure of lingual epithelia and chelonian feeding mechanisms. Methods: Light microscopical (LM) and scanning (SEM) and transmission (TEM) electron microscopical methods were used. Results: SEM revealed a distribution of lingual papillae all over the dorsal tongue surface. Single epithelial cells can be discerned, with short microvilli on their surface. LM studies show differences within the stratified epithelium between the lateral and the apical side of the papillae. In TEM, these differences become more obvious; while the basal and deep intermediate layer is similar in both sides of the papillae, mucus granules begin to form at the edge of the superficial intermediate layer at the lateral side. Cells containing fine secretory granules are visible there, too. On the other hand, at the apical side, only fine-granule-containing cells are visible. Conclusions: This study indicates that the histology and ultrastructure of the lingual epithelium of Trachemys scripta elegans are similar to that of other turtles adapted to freshwater environments but differ from those of turtles living in marine or terrestrial habits. These differences can be explained in terms of the adaptation of turtles to their particular life circumstances. Anat.

Histological and ultrastructural investigations revealed three different multicellular skin gland types in the salamandrid Pleurodeles waltl. The mucous glands are small, with one layer of secretory cells surrounding a central lumen; they produce the viscous and slippery mucus film that has various functions in amphibians. The serous glands can be divided based on their histological and ultrastructural characters into the granular gland Type I (GGI) and the granular gland Type II (GGII). The first type (GGI) is moderately sized and distributed throughout the body surface, with higher concentrations in the parotoid and back regions. In contrast, the second type (GGII) is very large (for Pleurodeles) and was found only in the tail, with highest concentration in the tail dorsum. Both granular gland types contain mainly proteinaceous materials but differ in their morphological features including size, shape, cellular organization and vesicle distribution, vesicle size and vesicle shape. Both GGI and GGII are especially concentrated in body parts that are presented to an attacking predator and are hypothesized to produce repellent to poisonous substances to thwart potential aggressors.