A new genus of Carnoyidae (Nematoda: Rhigonematida) with descriptions of Cattiena trachelomegali gen. n., sp. n. and C. trigoniuli gen. n., sp. n., parasites of Spirobolida (Diplopoda) from Vietnam

Cattiena gen. n., a new genus from the Carnoyidae, is described from the posterior gut of two genera of spirobolid diplopods from Vietnam. The new genus is characterised by: presence of eight somatic spine rows in the cervical region of both male and female, the four sublateral spine rows being better developed; presence of six cuticularised plates around the female oral opening; extremely posterior vulva; two anteriorly directed ovaries; isomorphic and isometric spicules; boat-shaped gubernaculum of similar form to the spicules; gubernaculum with a dorsal hole; well developed, smooth cephalic cap in the male and 15 copulatory papillae with three pairs located lateral, sublateral or subdorsal. The new genus has morphological affinities with Raonema Kloss, 1965, a poorly known genus from India, but is easily differentiated by the extremely posterior vulva and the presence of spine rows in the male. Two new species are described in the genus: the type, C. trachelomegali gen. n., sp. n. from Trachelomegalus sp. and C. trigoniuli gen. n., sp. n. from Trigoniulus sp. The two species differ primarily in the position of the vulva (consistently more anterior in the latter species), degree of development of the vulval flap, body length, tail length and in the relative development of the somatic spine rows.

ULTRASTRUCTURAL CHANGES IN THE MITOCHONDRIA OF CEREBELLAR PURKINJE CELLS OF NERVOUS MUTANT MICE

The maturation of cerebellar Purkinje cells of normal and nervous (nr/nr) mutant mice has been studied by light and electron microscopy. In the mutant, 90% of Purkinje cells selectively degenerate between postnatal days 23 and 50. Losses are greater in lateral than medial regions. Other cerebellar neurons appear normal. The first morphological abnormality recognized is the presence of rounded mitochondria in perikarya of some Purkinje cells of the mutant at 9 days after birth. By 15 days, all nr/nr Purkinje cells contain spherical mitochondria and begin to deviate from the normal maturational sequence. Elaboration of the extensive dendritic tree halts midway and newly formed axon collateral fibers degenerate. In the perikaryon, the basal polysomal accumulation and climbing fiber-somatic spine synapses are sometimes abnormally retained. Cisternae of the Golgi apparatus and rough endoplasmic reticulum cease to form aligned stacks, and decrease in number, while polysomes dissociate into free ribosomes. These changes are progressive, culminating in cell death. Although every nr/nr Purkinje cell demonstrates spherical mitochondria, some cells survive the critical period, retain a near-normal complement of organelles, and reacquire normal-appearing mitochondria. The disorder appears intrinsic to Purkinje cells since all major classes of synapses were identified before cell death.