Recently one ovigerous female of Laomedia astacina de Haan, 54 mm in total length, was collected at the estuary of Tatara river, Fukuoka City on August 8, 1963, In the laboratory it was kept in a finger bowl containing reserved sea-water. Next day the larvae of the first zoea were hatched, but the further developed, stages could not be obtained. The characters of the first zoea are as follows. It is 3.2 mm in total length, and 1.0 mm in carapace length. There are red pigment spots and diffused yellowish pigments on the antennule, thorax and abdomen. There is a tendency in the first zoea of Laomedia to a lengthening of the region between mouth and antenna which becomes extreme in Jaxea and Naushonia (Gurney, 1942). In Laomedia the whole body is remarkably long and slender. The carapace has a small rostrum which is almost inconspicuous in natural state. The eyes are immobible. The abdominal somites have no dorsal spines, but the pleurae of 1-5 somites are drawn out into procurved hooks. The hook on the pleura 1 is a little smaller than the others. The abdominal somite 6 is fused to the telson which is slender, notched medially, and armed with six processes on each side. The first or outer process is apparently fused to the telson. The processes 2-5 are shown as strong plumose spines articulated with the telson. There is no median spine. The peduncle of the antennule is unsegmented; the inner ramus is represented by a strong process, and the outer by bearing five apical setae. In the antennal peduncle there is an inner ventral spine at the base of the endopod, and the endopod ends in three long apical plumose setae. The antennal scale unsegmented, and there are ten long plumose setae subterminally. The mandible is asymmetrical. The incisor processes on both right and left sides are drawn out into a sharp sickle, and the molar process of the left side has four blunt teeth and other two spines. The endopod of the maxillule has three long terminal setae. The proximal endite has four terminal setae and another subterminal seta. The distal endite terminates in four large spines and bears subterminally one seta on the inner margin. The maxilla bears two setae on the anterior lobe of the proximal endite and four setae on both the posterior and anterior lobes of the distal endite. The exopod has two strong plumose setae on the anterior margin and has other delicate setae on the margin. In the maxilliped 1 the unsegmented exopod terminates in four long plumose setae. The endopod two-segmented, bearing four setae apically. In the maxilliped 2 the exopod terminates in four long plumose setae. The endopod two-segmented with two terminal setae. The first zoea of Jaxea and Naushonia bears very close resemblance to that of Laomedia, however there are differences in some points. 1) The abdominal somite 1-5 are surely provided with procurved hooks in Laomedia, whereas there is no pleopod on the first somite in Jaxea and Naushonia. 2) The telson has seven pairs of spines in Jaxea and Naushonia (Gurney and Lebour, 1939; Gurney, 1942), while six pairs in Laomedia. 3) In the antennule the outer ramus is apperently fused to the peduncle, and five apical setae are found in Laomedia, on the other hand in Jaxea and Naushonia the outer ramus jointed, and six apical setae are found.