This worm lives in a tube fashioned of sand grains, the tubes are in a vertical position, in the sand of inter-tidal regions, and at Beaufort, N. C., are often found in association with the similar tubes of Axiothella mucosa, another tubicolous annelid (Bookhout and Horn, 1949).

At times, the animals are abundant, but the number seems to fluctuate widely from year to year. Since the breeding season apparently is very short, it is advisable to collect large numbers of the worms immediately before the onset of the breeding season.

Burbanck et al. ( 1956) report that Clymenella was regularly collected at Rand's Harbor, Mass., over a six-year period.

According to Mead (1897), all mature individuals spawn during a restricted two- or three-day period which occurs between the latter part of April and the middle of May.

A. Care of Adults: Mature females have eggs which show through the body wall during the breeding season. The sexes should be segregated and the females placed in an aquarium which is supplied with sand. New tubes are rapidly built by the worms.

B. Procuring Gametes: Eggs are deposited on the surface of the sand, at the mouth of the tube. They may be left in sea water for several hours before insemination.

NORMAL DEVELOPMENT

A. The Unfertilized Ovum: The egg measures 150 microns in diameter. It is practically spherical, and is very opaque because of the large amount of yellow yolk. A closely fitting, thin, smooth membrane is present (Mead, 1897).

B. Fertilization and Cleavage: The sperm enters after the first maturation spindle has formed, and the polar bodies remain to mark the animal pole (Mead, 1897). Cleavage is equal and spiral, and no polar lobes are formed. Gastrulation is probably by epiboly. In general, the development is very similar to that of Amphitrite, according to Mead; see Figures 65 to 88 in his paper (1897).

C. Rate of Development: No precise information is available.

D. Later Stages of Development: The larva is a free-swimming trochophore, reported to be similar to the trochophore of Amphitrite.

BOOKHOUT, C. G., AND E. C. HOXN, 1949. The development of Axiothella mucosa (Andrews). J. Morph., 84: 145-183.

BURBANCK, W. D., M. E. PIERCE AND G. C. WHITELEY, JR., 1956. A study of the bottom fauna of Rand's Harbor, Massachusetts: An application of the ecotone concept. Ecol. Monog., 26: 213-243.

MEAD, A. D., 1894. Preliminary account of the cell lineage of Amphitrite and other annelids. J. Morph., 9: 465-473.

MEAD, A. D., 1897. The early development of marine annelids. J. Morph., 13: 227-326.