I. Cyprinodon varsegatus (broad killifish)

A. June through mid-July.

B. Developmental rate: Moderately rapid; hatches in 5-8 days.

C. Egg characteristics: Demersal; 1.3-1.5 mm. in diameter; spherical, slightly yellow; yolk almost transparent and colorless; fibrous, sticky coat; small oil droplets present; micropyle visible.

D. Special comments: Females with ripe eggs are rather difficult to obtain. The larvae live well in fingerbowls of sea water.

E. Pertinent Breder (1948); Newman (1907, 1915).

II. Opsanus tau (toadfish)

A. June and July.

B. Developmental rate: Very slow; hatches in 10-26 days.

C. Egg characteristics: Demersal; 5 mm. in diameter; large adhesive disc at center of vegetal pole, opposite micropyle; deep amber in color.

D. Special comments: Fairly readily obtained; the eggs are found attached inside submerged objects (tin cans, old boots, etc.), or they can be inseminated artificially (by allowing the eggs to flow from the opened ovary into a dish containing just enough water to cover them; fertilize after the eggs have attached to the dish).

E. Pertinent Clapp (1891, 1898, 1899); Sumner (1903); Wallace (1899) .

III. Scomber scombrus (mackerel)

A. Mid-May to June and very early July.

B. Developmental rate: Rapid; usually hatches in 60 to 72 hours.

C. Egg characteristics: Pelagic; 1.2 mm. in diameter; faintly pink in color, transparent; one large oil globule; very sensitive to changes in temperature, 16• C. being optimum.

D. Special comments: The eggs are fairly readily obtained; females contain enormous numbers of eggs, but they must be stripped at the fish traps. Even at optimum temperatures, the mortality rate is high.

E. Pertinent references : Newman (1915, 1918); Russell (1939); Worley (1933).

IV. Stenotomus chrysops (scup)

A. Early June.

B. Developmental rate: Very rapid; hatches in 48 hours.

C. Egg characteristics: Pelagic; 0.8 mm. in diameter; colorless and very transparent; one large oil droplet.

D. Special comments: Mature females are rather difficult to obtain, but large numbers of eggs may be obtained from a single female. The fish must be stripped as soon as the eggs are ripe. Hatched embryos will live for a few days in fingerbowls of sea water.

E. Pertinent

V. Strongylura marinus (billfish)

A. June.

B. Developmental rate: Slow; the time of hatching has apparently not been recorded.

C. Egg characteristics: Demersal; 3 mm. in diameter; very clear and transparent; long tufts of adhesive threads.

D. Special comments: Not very common; probably it is best to strip and inseminate the eggs at the fish traps, although this can be done later, at the laboratory. The percentage of fertilized eggs is not very high, but the enormous numbers of eggs obtained from one female often assure a good supply of eggs. Embryos can be raised to the hatching stage.

E. Pertinent references Breder (1948).

VI. Syngnathus fuscus (pipefish)

A. Mid-May through June or possibly early July. Males with young in their brood-pouches have been found in July and early August. B. Developmental rate: Not known.

C. Egg characteristics: Pelagic; carried by male in a ventral brood-pouch; 0.75-0.85 mm. in diameter; nearly opaque; contains numerous orange oil droplets.

D. Special comments: Large numbers of eggs and larvae are found in the brood-pouches of the males&endash;as many as 200. Eggs apparently cannot successfully be removed from the brood-pouch until the yolk sac is completed, but after that time, they will develop in fingerbowls of sea water.

E. Pertinent Agassiz and Whitman (1885); Cohn (1904); Huot (1902); Cunningham (1895).

AGASSIZ, A., AND C. O. WHITMAN, 1885. The development of osseous fishes. I. The pelagic stages of young fishes. Mem. Mus. Comp. Zool., Harvard, 14: no. 1, part 1, pp. 1-56.

BREDER, C. M., JR., 1948. Field Book of Marine Fishes of the Atlantic Coast from Labrador to Texas. G. P. Putnam's Sons, New York. (Rev. ea.)

CLAPP, C. M., 1891. Some points in the development of the toad-fish (Batrachus tau). J. Morph., 5: 494-501.

CLAPP, C. M., 1898. Relation of the axis of the embryo to the first cleavage plane. Biol. Lectures M. B. L., Wood's Holl, Mass., pp. 139-151.

CLAPP, C. M., 1899. The lateral line system of Batrachus taut J. Morph., 15: 223-264.

COHN, L., 1904. Ueber die Bruttasche von Syngnathus typhle. Anat. Anz., 24: 192-199.

CUNNINGHAM, J. T., 1895. Experiments and observations made at the Plymouth Laboratory. II. The development of the egg in flat fishes and pipe-fishes. J. Mar. Biol. Assoc., 3: 258-270.

HUOT, A., 1902. Recherches sur les poissons lophobranches. Ann. des Sci. Nat., Zool., ser. 8, 14: 197-288.

NEWMAN, H. H., 1907. Spawning behavior and sexual dimorphism in Fundulus heteroclitus and allied fish. Biol. Bull., 12: 314-348.

NEWMAN, H. H., 1915. Development and heredity in heterogenic teleost hybrids. J. Exp. Zool., 18: 511-576.

NEWMAN, H. H., 1918. Hybrids between Fundulus and mackerel. A study of paternal heredity in heterogenic hybrids. J. Exp. Zool., 26: 391-421.

RUSSELL, A., 1939. Pigment inheritance in the Fundulus-Scomber hybrid. Biol. Bull.,., 77: 423-431.

SUMNER, F. B., 1903. A study of early fish development. Experimental and morphological. Arch. f. Entw., 17: 92-149.

WALLACE, L. B., 1899. The germ-ring in the egg of the toad-fish (Batrachus tau). J. Morph., 15: 9-16.

WORLEY, L. G., 1933. Development of the egg of the mackerel at different constant temperatures. J. Gen. Physiol., 16: 841-857.