The distribution of neurosecretory cells in the head of the blind cave crayfish, Cambarus setosus, was determined. The degen- erate eye in this blind crayfish also was described. The cuticle is thinner at the tip of the eyestalk than elsewhere, suggestive of the previous exist- ence of a cornea. The degenerate optic nerve does not originate in the disrupted hypodermis. A distinct basement membrane marks the proxi- mal border of the degenerate eye. The cuticle has distinct folds in the region of the degenerate eye, suggestive of an earlier facetting. The sinus gland is morphologically the same as that found in eyed cray- fishes. The lamina ganglionaris, medulla externa, and medulla interna show signs of degeneration, the former most of all. In 1890 Parker described the morphology of the degenerate eyes in the blind cave crayfishes Orconectes pellucidus and Cambarus setosus. Since 1890, however, no one has probed further into the structure of the eyestalks of blind crayfishes. The sinus gland, an im- portant neurohemal organ in higher crustaceans with well-developed eyes, has not been described from blind crayfishes. Hanstr6m (1933, 1937), who discovered the sinus gland, described its structure from a wide variety of crustaceans including an eyed crayfish. However, blind cave forms were unavailable to him. Since the early 1950's interest in crustacean neurosecretion has been very high. In spite of this fact, neurosecretion in blind hypogeal species has not been the subject of even one investigation. The distribution of neurosecretory cells in the supraesophageal ganglia of eyed crayfishes has been re- ported by Durand (1956) for Orconectes virilis and by Fingerman and Aoto (1959) for the dwarf crayfish, Cambarellus shufeldti. In a