ABSENCE OF THE EPITHELIAL HYPOPHYSIS IN A FETAL DOGFISH ASSOCIATED WITH ABNORMALITIES OF THE HEAD AND OF PIGMENTATION

¹ From the Department of Anatomy, Harvard Medical School

1. An anomalous fetus of the spiny dogfish (Squalus acanthias) is described in which there are malformations of the head comprising cyclopia, astomia, and abnormalities of the hypophysis.

2. The abnormalities of the hyophysis involve:—

(a) The total absence of the oral components of the gland, and

(b) A neural lobe which is deformed and possesses no saccus vasculosus. The conclusion is drawn that the neural lobe has not undergone normal differentiation because it has been deprived of its usual association with the buccal hypophysis.

3. The specimen is albino, displaying a diminished number of chromatophores in a state of persistent contraction. This finding indicates that the melanophore-controlling principle in the dogfish is a derivative of the buccal components of the pituitary.

4. Only one other instance of total spontaneous suppression of the oral hypophysis is described in the literature, namely, in a pig fetus (Holt, 1921). In human fetuses anencephaly occurs not infrequently but is associated with suppression of the neuro-hypophysis instead of with the adenohypophysis.