fission (fis's hun)

A mode of generation or of cell division in which the organism separates into two or more equal parts, each of which becomes developed to the size and form of the original, binary f. F. into two parts, multiple f. F. into many to cleave.] parts. [Lat, U ier, from Undere, fi u'ra. See fi ure, f. abdominal is. A congenital deficiency in the abdominal wall through which the contents of the abdomen protrude, f. abdominal is completa. A congenital deficiency in the anterior abdominal wall from the thorax to the pelvis, f. ani. See fi ure of the anus, under fi ure, f. antitragohelicina. A f. in the cartilage of the external ear between the proce us helicis caudatus and the antitragus. f. cerebelli longitudinal is. A broad, shallow groove on the inferior surface of the cerebellum separating the hemispheres, f. cerebri lateral is anterior. The anterior or ascending branch of the fi ure of Sylvius, f. cerebri lateral is posterior. The posterior or horizontal branch of the fi ure of Sylvius. f. dors i mesal is. In teratology, a fi ure in the middle line of the back. f. genital is, i. The cleft of the vulva. 2. A fi ure of the male genitals, producing when complete a form of hermaphroditism, f. incisiva facial is. A fi ure sometimes found on the outer surface of the superior maxilla, corresponding to the incisor fi ure, fi urae interlobulares hepatis. Fi ures' which separate the lobes of the liver, f. irid is. See coloboma irid is, under coloboma. f. laryngea pharyngis. The pharyngeal opening of the larynx, f. lateral is. The fi ure of Sylvius, f. mas to idea squamosa. A small fi ure in the line of junction of the mastoid and squamous portions of the temporal bone. f. or is. The mouth in its restricted sense, f. pal at in a. See cleft palate, f. palpebra rum. The cleft between the eyelids, f. pet rob as i laris. A fi ure, partly filled by connective ti ue or o icles, between the petrous portion of the temporal bone and the occipital and sphenoid bones, f. petroso-angular is. A fi ure between the apex of the pyramidal part of the petrous portion of the temporal bone and the great wing of the sphenoid bone. f. pterygoidea, f. pterygopalatina. The space between the lower ends of the pterygoid plates of the ethmoid bone, into which the pterygoid proce of the palate bone fits. f. pudendi. The cleft of the vulva, f. spinal is. See spina bifid a. f. stern i, f. stern i congenita. See congenital fi ure of the sternum, under fi ure, f. thoracis. In teratology, a congenital deficiency in the chest wall. f. tympanico mas to idea. A small fi ure between the mastoid portion of the temporal bone and the posterior margin of the external auditory meatus, in which are the openings of the canal is mas to ide us. f. urethrae completa. See epispadias penis, f. urethrae in comp let a. See epispadias gland is. f. urethrae superior. See epispadias. f. ventral is. See anterior median fi ure of the spinal cord, under fi ure, f. ventri lateral is.