These animals are found between tide levels, in pile scrapings and under stones. They may be distinguished from Lepidonotus, which is collected in the same localities, by having 15 rather than 12 pairs of scales. The sexes are separate.

Mid-April through May. The season is about one week earlier than that of Lepidonotus (Bumpus, 1898).

Ripe females can be recognized by the bright pink color of the ventral surface. Eggs teased from the body cavity are easily fertilized, according to Mead (1898). Shedding of eggs may be induced by the methods suggested for Lepidonotus (p 81).

A. The Unfertilized Ovum: The egg is pink and rather clear, with minutely granular yolk. It is small; Sars (1845) records 50 microns for the egg diameter of a European form of this species, and diameters ranging between 56 and 78 microns are reported by McIntosh (1900) at St. Andrews, N. B.

B. Cleavage: Cleavage is equal and spiral, and no polar lobes are present. Gastrulation is probably by invagination.

C. Rate of Development: No precise data are available, although Mead (1898) states briefly that the eight-cell stage was attained in less than two hours.

D. Later Stages of Development: Mead (1897) reports that the development of Harmothoë is very similar to that of Lepidonotus. The larval stages are well described and illustrated by McIntosh (1900) and Thorson (1946) . Young trochophores are positively phototropic (McIntosh, 1900).

BUMPUS, H. C., 1898. The breeding of animals at Woods Holl during the month of May, 1898. Science, 8: 58-61.

McIntosh W. C., 1900 1923. A monograph of the British Annelids, Pt. II. Polychaeta. Dulau & Co., Ltd., London. (Eight volumes.)

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

MEAD, A. D., 1898. The breeding of animals at Woods Holl during the month of April, 1898. Science, 7: 702-704.

SARS, M., 1845. Zur Entwicklung der Anneliden. Arch. f. Naturgesch., 11 Jahrg., 1: 11-19.

THORSON, G., 1946. Reproduction and larval development of Danish marine bottom invertebrates, with special reference to the planktonic larvae in the Sound (0resund). Medd. f. Komm. Danmarks Fiskeri. og Havunders., Ser. Plankton, 4: (Nr. 1) 1-523.