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CHARACTERS OF LARVAE ACCORDING TO FAMILIES 

 Cucumariidae sensu lato 



Development with lecithotrophic larva : The eggs are large, float on the 

 surface layer, 300-450 |j,m in diameter. The animal pole may be tinted 

 reddish-orange, but the rest of the larva is greenish. Either the larva is entirely 

 and uniformly covered with short cilia or a few transverse ciliated bands 

 occur in its lower half. The pentactula has five primary tentacles, which are 

 distally bifurcate and provided with numerous papillae, as well as one or two 

 ambulacral podia, located above the anal opening and connected with the 

 medioventral ambulacral canal. 



Two species of this family — Cucumaria japonica Samper and Eupentacta 

 (= Cucumaria) frudatrix (Djakonov and Baranova) — are found in Peter the 

 Great Bay. 



Stichopodidae 



Development with planktotrophic larva : The eggs are about 100 |J.m in di- 

 ameter and spherical. The larva is transparent. The postoral processes are best 

 developed in the auricularia (Stichopus japonicus). Calcite lumps of various 

 shapes and sizes lie at the base of the anal lobe on both sides. The posterior 

 end of the larva is flat. Five pairs of elastic spheres appear in the late 

 auricularia. Five transverse ciliated bands are present in the doliolaria and the 

 elastic spheres and calcite lumps persist. The pentactula has five primary 

 tentacles and one ambulacral podium; elastic spheres are absent while calcite 

 ossicles and ciliated bands persist. 



The only member of this family found in Peter the Great Bay is Stichopus 

 japonicus Selenka. The auricularia of this species has been described by 

 Kume and Dan (1968). A more complete description of the development of 

 S. japonicus is given below. 



FAR EASTERN TREPANG 

 STICHOPUS JAPONICUS SELENKA 



Mature eggs in the trepang are nontransparent, about 150 |im in diameter. 

 Artificial fertilization is not always successfiil. Thermostimulation is the re- 

 liable method for obtaining viable larvae, whereby the female releases mature 

 eggs. The blastula forms 6-8 hrs after fertilization at a water temperature of 

 20-2 1°C. The blastula is spherical but gradually elongates in the animal- 



