Observations on the lateral-line sense organs of the Salamander Neurergus crocatus crocatus Cope (Amphibia: Urodela).

The lateral-line system of the subadult and adult Neurergus crocatus crocatus Cope is retained throughout the life. It is constructed of pear-shaped sense organs or neuromasts which in the subadults are confined entirely to the epidermis with their apices opening distally to the exterior at the general level of the epidermal surface whereas in the adults they are embedded proximally more than halfway in the dermis with their distal apices opening into shallow grooves slightly below the regular epidermal surface. Dimensional differences are also observed between these organs in both stages. The neuromasts are constructed of 4 distinct cell types: sense cells, basal cells, sustentacular cells and mantle cells. These cells differ morphologically, structurally, topographically and functionally. The sense cells are clup-shaped, sensory, central in position and couched among the extremely elongated supporting basal and sustentacular cells, all of which are covered laterally by the extremely slender protective mantle cells. In both the mature and larvae, differences are observed among these cells in their size, number, location and arrangement. The sense organs are richly-supplied and well-nourished with vascular and nervous supplies.