similar to those of A. aureum (Marcus, 1944). The ciliated prostomial groove leads directly to the ciliated pit, but the cilia of the groove are partly obscured by its posterior margin which partly covers the groove.

Encystment of a worm isolated on a slide was observed. It coiled itself into a tight ring, with the flat ciliated ventral surface of the prostomium closely apposed to the inner surface of the last segment of the body (Fig. 1). A very thin cyst membrane enclosed the worm. Fracturing the cyst membrane freed the worm, which again became active on the slide. Because of its starved condition, both the worm and the cyst were very small, but otherwise it generally resembled the encysted stage of A. hemprichii, described by Herlant-Meewis (1950, 1951).

In the later cultures there occurred a bifurcated monster (Fig. 4). Bifurcation was at the anterior end, the body being united at the fourth—i.e., the third setigerous segment. There were six segments posterior to the bifurcation. Normally, n, the number of segments anterior to the budding zone is 7. The prostomium of one of the monster's heads showed further partial bifurcation. I did not observe the cerebral ganglia in this head, nor did I observe the functioning of the gut. The worm died after a few days. I do not know of any other record of bifurcation in Aeolosomatid worms. Usually they reproduce asexually by budding, and I have never observed sexual worms of A. niveum. The monster, however, must have been formed by the abnormal development of an egg (Stephenson, 1930: 543–544).

Aeolosoma kashyapi Stephenson 1923. Fig. 2.

The present worm is similar to that previously identified as A. kashyapi (Stout, 1952). Sexual worms were observed in June and October. In June, only the clitellum and ovum were present. In October, sperm morulae were also present. Marcus (1944: 92) found sexual worms of A. kashyapi in December and January. There is no indication, therefore, of a seasonal cycle.

In the living worm, the ovum, or ovocyte as it is called by Marcus, extends from just in front of the setae of the fifth segment to just behind the setae of the sixth segment. It is asymmetric, lying on the ventral and left side of the gut and closely apposed to it (Fig. 2). It is a large, flattened body, roughly oval in outline. Seen in the living worm, the ovum appears much denser between the gut and the body wall than where it is seen over, or under, the gut. However, in my worms, the ovum, filled with yolk granules, was perfectly homogeneous throughout. Only a single ovum was observed in each worm. A thickening of the body wall—the clitellum—is restricted to the left side of the body—i.e., next to the ovum. Sperm morulae, at different stages of development, were observed throughout the body cavity. No other stages of sexual development were observed. These observations are similar to those of Marcus (1944: 115), except that he shows the ovum, or ovocyte, as consisting of a dark lateral part and a lighter median part. This appearance is, as I have described, a deception. The ovum is, as shown by Aiyer (1929: 18) for A. travancorense, an homogeneous body.

A cyst of A. kashyapi was observed in the later cultures. It was about 150–170 mu in diameter and resembled very closely the cysts of A. hemprichii described by Herlant-Meewis (1950, 1951).