DEVELOPMENT AND FUNCTION OF NEUROSECRETORY SITES IN THE EYESTALKS OF LARVAL PALAEMONETES (DECAPODA: NATANTIA)

Abstract

1. The histogenesis of eyestalk organs in Palaemnonetes vulgaris, P. pugio, P. intermedius, and P. kadiakensis is essentially the same. Palaemnonetes paludosus, having an abbreviated larval development, follows the same sequence of events in a shorter period of time.2. The developing eyestalk of Palaemonetes has two consistent, characteristic features: (a) a single, large, nionopolar, secretory neuron that becomes active during the first larval stage, and (b) a sac-like vacuole in the sensory pore X-organ that appears to be the site of storage and release of secretory products, from the first larval stage through adult life.3. The sensory pore X-organ develops from neuroblasts of the eyestalk ganglia. It appears 5 or 6 days before hatching. It is located dorsally and remains in this position throughout larval development. Secretory droplets appear in the SPX vacuole during the first larval stage. The accumulation of droplets increases throughout larval life.4. The sinus gland is not recognizable until the...