''(EXPERIMENTAL AND HISTOLOGICAL STUDIES ON THE NERVOUS AND REPRODUCTIVE SYSTEMS OF THE PROTOCHORDATE STYELA PLICATA (LESUEUR)'' (UROCHORDATA-ASCIDIACEA

Abstract

Abu KIR Bay was found to be a much more suitable area for ascidians collection. Specimens of Styela plicate were examined carefully to describe both the nervous and the reproductive systems in situ, from one hand and to find out whether gonadotrophin plays a role in the natural biology of this species on the other hand.

The macroscopical preparations of the specimens were - - ------ ------ ----- - -- -• -- - - critically examined to correlate the macroscopical appearance of the

two systems with the microscopical ones and to detect the changes which may accur to the constituents of these systems during the different seasons of the year.

The nervous system:

The nervous system of Styela plicate is generally referred to as the neural complex being formed of a neural gland and a nerve ganglion. This complex is comapratively very small in size and occupies the region in between the oral and the atrial siphons close to the dorsal surface. It is embedded in the mantle wall and consists of

an elongated mass from which arise the anterior, the postenior and the lateral nerve trunks at different levels.