Raikow Robert J, Swierczewski Edward V
Department of Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260.
J Morphol. 1975 Apr;145(4):435-439. doi: 10.1002/jmor.1051450404.
The cephalic clasper of the male Chimaera collei is a cartilaginous rod equipped with denticles and presumably used to grasp the female during copulation. It is attached to the skull by ligaments but there is no joint cavity or articular surface. It has no intrinsic muscles, its movements being provided by attachments to muscles of the lower jaw and labial cartilages. The cephalic clasper is apparently elevated by a branch of the preorbitalis muscle, whose main function is to elevate the lower jaw. It appears to be forcefully depressed during copulation by M. levator anguli oris, whose primary function is to move the labial cartilages. When not in use, the cephalic clasper is held passively depressed by an elastic tendon from M. preorbitalis. In the female the cephalic clasper is represented by an apparently functionless rudiment.
科氏银鲛雄性的头部交合突是一根带有小齿的软骨棒，推测在交配时用于抓住雌性。它通过韧带附着于头骨，但没有关节腔或关节面。它没有固有肌肉，其运动由附着于下颌肌肉和唇软骨的肌肉提供。头部交合突显然由眶前肌的一个分支抬起，该肌的主要功能是抬起下颌。在交配时，它似乎被提口角肌强力压低，该肌的主要功能是移动唇软骨。不使用时，头部交合突被眶前肌的一条弹性肌腱被动压低。在雌性中，头部交合突表现为一个显然无功能的残迹。
