Sense organs of the nematodes Trichinella pseudospiralis Garkavi, 1972 and T. nativa Britov et Boev, 1972

The structure and distribution of the sense organs of the head and the tail of two day-old Trichinella species (females) have been determined by transmission (TEM) and scanning (SEM) electron microscopy. In both species occur 16 cephalic sense organs, which contain three modified dendritic processes, in addition to the amphids. The nerve cell bodies are situated in the area above the nerve ring. The amphid contains ten dendritic processes. The sense organs open to the external environment by pores through the cuticle. Above the bulbous tip, the dendritic processes are surrounded by hypodermal cells. They enter posteriorly the pseudocoelom and join in subventral, subdorsal and two sublateral nerves, with transparent nuclei, in the area above the nerve ring. The distribution of the sense organs of larvae from the muscles and from the uterus is similar to that of the adults. The dendritic processes are short, most of their distal chamber is compacted with a dense, filamentous material. The rectum in the tail end of the female is innervated from the dorsal ganglion composed by multipolar cells with numerous dendrites and a single axon. Close to the excretory pore occurs a hemizonid which consists of six to eight dendrites and is situated between the hypodermis and the muscles. This organ has not been found in the larva.