The muscles of the mouse hard palate were studied in 12 adult mice by observations based on light microscopy and macroscopy. As a result, an undescribed muscle was found and named the “oblique palatine muscle” by the authors. The running direction of this muscle indicated a functional role whereby the incisive foramina would be dilated by traction of this muscle. On the other hand, it was noted that the bundle of the transverse palatine muscle pressed the incisive papilla backwards and the incisive foramina were shut by traction of this muscle. The authors assume that the functional role of the taste buds in the incisive papilla is essential for the protective reflex in the nasopalatine duct.

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The constitution of the muscles of the thigh were examined in 24 male and 26 female crab-eating monkeys (Macaca fascicularis). The boundary of the origin and the insertion of the muscles were defined. The composition of the spinal nerves was observed in two specimens. The n. femoralis, n. obturatorius and n. flexoris femoris arose from the lumbar plexus and ranged from the third to the fifth, the fourth to the sixth and the fifth to the seventh lumbar nerves, respectively. The segmental innervation of the muscles in the same specimens was studied. The muscles of the thigh were categorized into seven groups based on the innervation and their relative positions. More cranially arising muscle groups received a higher segmental nerve. They were inserted more medially because of rotation of the hip joint during embryogenesis. More distally and laterally inserting muscles within the same muscular group received a lower segmental nerve than the others. These findings suggest a uniform mechanism in the myotome arrangement of the lower limb during embryogenesis in man and the monkey. On this basis, the dual innervation and intermuscular septum in the thigh are well explained by the developmental process.

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The surface topography of human primordial germ cells (PGCs) during the migration period was observed by scanning electron microscopy, paying special attention to the association of PGCs with somatic cells. PGCs in the stationary phase of their migration were spherical in shape and measured 12μm in diameter. The cell surface was generally smooth with some microvilli. On the other hand, PGCs in tne moving phase revealed an indefinite shape and often possessed pseudopodia. Their surface was scmewhat undulating and microvili were rarely found. PGCs were often seen to make contact with neighboring mesenchymal cells during their migratory course, especially at the root of the dorsal mesentery or other areas near the gonads. Two types of contact were observed: direct adhesion of a mesenchymal cell body to a PGC, and indirect adhesion by cytoplasmic protrusions from a mesenchymal cell to a PGC. In the latter case, three types of protrusions, i. e. lobopodia, filopodia, and lamellipodia, were observed. These contacts between PGCs and somatic cells may be related to the mechanisms of migration of PGCs.

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Seven adult platyrrhine monkeys (Cebus apella) of both sexes, had their right zygomatic bone fractured and displaced by surgery. After a time lapse of 7 months, they were sacrificed, macerated, and the crania were studied by means of radiography, the split-line technique, and scanning electron microscopy.
The changes on the operated side, observable by radiography, consisted mainly of a discrete disorganization of the zygomatic bone trabeculae and diminution of the radiopacity of the lateral-inferior margin of the orbit, of the zygomaticoalveolar crest and of a line that accompanied the zygomaticomaxillary suture.
The split-line technique, applied to the operated osseous region, demonstrated a fibrous disarrangement of the body of the zygomatic bone and of the fractured and repaired areas. At the level of the zygomatico temporal and zygomaticomaxillary sutures, the split-lines converged to the extremity of the involved processes (those which showed volumetric increases) and did not pass along the other side, as on the normal side. The convergence of the lines associated with the volumetric increase displayed an adaptation to the concentration of mechanical forces in the extremity of each process.
Scanning electron microscopy of superficial areas of the decalcified and nondecalcified zygomatic bone revealed changes on the operated side compared to the control one. These included irregular and disorganized compact bone showing depression, micro-elevations and irregular foramina, still evidencing a fibrillar arrangement without a defined structural pattern as regards the architectural orientation.

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The dermal side of the chick embryonic skin was observed by scanning electron microscopy (SEM) after the removal of dermal components. Epidermis free of dermis was prepared as follows: Tissues were fixed, hydrolyzed with hydrochloric acid (HC1), digested with collagenase or trypsin, and processed for SEM observation. The epidermis from the anterior tarsometatarsus and the foot pad was examined. The base of the tarsometatarsal epidermis of a 13-day-old embryo was smooth except for the ridge demarcating each large overlapping scale. The base of each basal cell of 18- to 20-day-old embryos, bulged in hemispherical fashion on the dermal side. The undulation of the base of the epidermis (i. e. the formation of the dermal papillae) was not prominent in the tarsometatarsal epidermis. In the foot pad, small round depressions, each corresponding to a reticulate scale, were observed on the dermal side of the epidermis. The bottom of a depression was smooth in a 13-day-old embryo. After 18-20 days of incubation, the downgrowth of the epidermis occurred. Many pits corresponding to the dermal papillae were clearly seen. These observations show the morphological diversity of the epidermis in its dermal side during the development. In addition, HC1treatment followed by protease digestion is useful in the study of morphogenesis of the epidermis.

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