On the Structure of the Excretory Organs of Amphioxus

Abstract

The excretory organs of Amphioxus were independently discovered by Weiss and Boveri in the year 1890 (1 and 13). Weiss described a series of small tubules regularly distributed at the top of each secondary tongue-bar throughout the region of the pharynx. The tubules are situated, for the most part, in the wall separating the dorsal cœlom from the atrial cavity ; they lie, therefore, between the cœlomic and the atrial epithelium, generally separated from the latter by a network of fine blood-vessels. These kidney tubules open into the atrium by a pore just opposite the dorsal end of the secondary gill-bar. Weiss suspected the presence of an internal opening, but could not find it. The physiological significance of these organs he established by means of feeding experiments with carmine and other colouring matters.