Both these species may be obtained readily by digging near low water mark at the Northwest Gutter or Sheep Pen Cove, near Woods Hole, Mass., at Lagoon Pond, on Martha's Vineyard, or at Rand's Harbor. L. roseola, which is small and rose-colored, is usually found under stones, and L. inhaerens, which is 10 to 20 cm. in length and white in color, is found burrowing in sand and occasionally in black mud. Both species are hermaphroditic, but neither is self-fertile. The American form of Leptosynapta inhaerens has been considered by some workers to be distinct from the European form with this name, and perhaps should be called L. tenuis (Ayres). Leptosynapta roseola is sometimes referred to as Leptosynapta (Epitomapta) roseola (Verrill).

The height of the breeding season in the Woods Hole region is at the end of June and early in July (Clark, 1899), but mature gametes are probably available throughout both months (Bumpus, 1898; Coe, 1912).

A. Care of Adults: The animals are very sensitive to environmental conditions and will fragment if they are not handled with extreme care. They can be kept in aquaria provided with running sea water and a deep layer of clean sand.

B. Procuring Gametes: The gonads, in the form of long, contractile white strands, are visible through the transparent body wall during the breeding season. If the body wall overlying them is punctured, the gonads will ooze out. Dissection of the strings with fine needles releases the gametes. In some animals, the gonad strings will contain mature sperm and immature ova; in others, they are full of eggs and the sperm-bearing parts are inconspicuous.

Free-swimming larvae have been raised from artificially-inseminated eggs of L. roseola (Coe, 1912), but for L. inhaerens it is necessary to obtain naturally-shed ova. Spawning in the latter species begins between 3 and 4 o'clock in the afternoon and continues until 5 or 6 P.M. In the laboratory, it is most frequently observed on the first two days following collection, although it does occur occasionally after that (Runnstrom, 1927). The males shed first and continue for a longer period than do the females. Details of the natural spawning of L. roseola have not been recorded.

C. Preparation of Cultures: Artificially-obtained eggs of L. roseola may be inseminated by adding a few drops of sperm suspension to a dish of eggs. Mix well, allow the eggs to settle, and then decant the supernatant fluid. Add filtered sea water. Naturally-inseminated eggs of either species can be collected with a pipette and transferred to a fingerbowl of filtered sea water. The cultures should be stored on a sea water table.

When free-swimming forms appear, pour the upper layers of the culture, containing them, into another dish. Fill the dish with fresh sea water. No feeding is necessary since the larvae develop through metamorphosis exclusively on their own yolk content.

A. The Unfertilized Ovum: The egg of L. inhaerens is very transparent and fragile. It is surrounded by a narrow coat of jelly. The ovum, on removal from the egg-string, is not quite spherical and measures between 190 and 209 microns in its longest diameter. The germinal vesicle is very large and contains a conspicuous nucleolus.

B. Cleavage: Segmentation is total and equal in both species. It is reported to be very regular in L. inhaerens (Coe, 1912); gastrulation is by invagination, and a free-swimming gastrula is produced (Runnström, 1927).

C. Rate of Development: Little has been recorded concerning the rate of development for these species. However, the free-swimming gastrula of L. inhaerens can be seen about 24 hours after fertilization.

D. Later Stages of Development and Metamorphosis: Both species produce free-swimming larvae. The three-day larva of L. inhaerens is barrel-shaped, with four distinct transverse bands of cilia. NO auricularia larva is developed. The free-swimming life is short and the larva remains near the bottom. Illustrations of the larval development of L. inhaerens may be found in a paper by Runnström (1927).

E. Pre-Adults: Metamorphosed animals up to 5 cm. in length may be collected at night, swimming near the surface in Eel Pond (Costello, 1946).

BUMPUS, H. C., 1898. The breeding of animals at Woods Holl during the months of June, July and August. Science, 8: 850-858.

CLARK, H. L., 1899. The Synaptas of the New England coast. Bull. U. S. Burl Fish., 19: 21-31.

CLARK H. L., 1907. The apodous holothurians. A monograph of the Synaptidae and the Molpadiidae. Smithsonian Contr. to Knowledge, 35: no. 1723 pp. 1-231.

COE, W. R., 1912. Echinoderms of Connecticut. Conn. State Geoi. and Nat. Hist. Surv., 19: 1-147.

COSTELLO, D. P., 1946. The swimming of Leptosynapta. Biol. Bull., 90: 93-96.

RUNNSTRÖM, S., 1927. Über die Entwicklung von Leptosynapta inhaerens (O. Fr. Müller). Bergens Mus. Arb., 1927, Naturv. rekke, Nr. 1, pp. 1-80