猪的指(趾)枕及蹄的形态秸构

主枕的枕底为前尖后宽略呈三角形,其后方无毛处与皮肤的界限不清。枕的厚度,表皮层为最厚,枕皮下层次之,真皮层为最薄。主枕的枕底,外侧的(第四)都略高于内侧(第三)的。悬枕的表皮层和真皮层的厚度二者略等。悬枕各层的厚度及大小,都是第五大于第二的。主蹄的蹄冠比马的明显并特别宽大,其高与蹄壁的高度略等。在蹄冠的下三分之二处,有比蹄壁更为致密的角小叶。蹄壁外观略呈三角形,其表皮层的厚度于蹄尖处为最厚。叶状层有发达的角小叶。蹄底呈弯镰刀形,尖向后上,它的白线不如马的显著。两个主蹄的蹄尖大部都有内向的趋势,而外侧(第四)的蹄尖都向前伸出。蹄壁与蹄底之间的角度,后蹄略小于前蹄。悬蹄是第二都小于第五,呈圆锥形,锥尖向下。悬蹄的蹄底不与地面平行。指(趾)间面的蹄壁向着背侧。第二指(趾)的蹄尖离地面的距离都高于第五指(趾)的。

MORPHOLOGY AND STRUCTURES OF THE DIGITAL CUSHIONS AND UNGULAE IN PIGS

The soleae pulvini of the chief cushion are roughly triangle-shapedwith their frontal ends norrowed and back ends widened.There is no distinctboundary between the hairfree area behind the solea and the skin.Among thethree layers of the cushion,the epidermis ranks first in thickness,the subepi-dermal layer the second and the derma the third.The external(the fourth)solea pulvini is always slightly higher than the internal(the third)one.Theepidermis and the derma of the accessory cushion are roughly the same inthickness.The thickhess of all the three layers and the size of the fifth accessorycushion are always superior to those of the second accessory cushion.The corona of the chief ungulae are broad and more distinct than thosein the horse and their height is roughly equal to that of the ungular wall.The laminae cornea at the lower two-thirds of the corona are more compactthan the paries ungulae.The paries looks like triangle in shape and its epid-ermis becomes the thickest at the ungular tip.There are well-developedlamellae corneae in the stratum lamellatum.The solea ungulae are sickle-shaped and the tip of the sickle points backwards and upwards,and theirwhite zones are not so remarkable as those in the horse.Both of the twotips of the two chief ungulae tend to point inwards in most cases whereas theexternal(the fourth)tips always tend to extend forwards.So far as the anglebetween the paries and the solea ungulae is concerned,that of the hind legs isrelatively smaller than that of the fore legs.The second accessory ungulaeare always smaller than the fifth ones and hoth are cone-shaped with the tipof the cone pointing downwards,The solea of the accessory ungulae are not para-llel to the ground surface,and the paries on the inter-digital surface facesdorsally.The distance from the hoof tips to the ground of the second digits isalways longer than that of the fifth digits.