EARLY STAGES OF PINK SHRIMP FROM FLORIDA WATERS 



EGG .\ND LARVAL STAGES 



325 



ABBREVIATIONS USED IN ILLUSTRATIONS 



al — first antenna 



a2 — second antenna 



ab — abdomen 



c — carapace 



cli- — chela 



dt — digestive tract 



e — eye 



en — endopod 



ex — exopod 



fr — frontal organs 



fu — furca 



gp — gill plate 



la — labium 



Im — labnmi 



md — mandible 



mp — mastigobranchial 



plate 

 mxl — first maxilla 



mx2 — second maxilla 



mxpl — first maxilliped 



mxp2 — second maxil- 

 liped 



mxp?) — rliirtl maxil- 

 liped 



o — ocellus 



ped — pedmicle 



per — pereiopods 



])1 — pleopods 



pr — protopod 



r — rostrum 



sc — scaphognathite 



st — statocyst 



su — supraorbital spine 



th — thorax 



u — uropods 



EGG 



Several hundred eggs were obtained from the 

 spavniing of mature female pink shrimp in the 

 laboratory. Fifty-three viable eggs measured 

 from 0.31 to 0.33 millimeters in diameter. The 

 viable eggs are yellow brown in color and opaque, 

 although when light is reflected in a certain way, 

 the chorion shows the blue hue reported by Pear- 

 son (1939) for the eggs of P. setiferus. 



The complete development of the fertilized egg 

 was not observed, since the eggs were already in an 

 advanced state when found. The development of 

 eggs of Penaevfi jnponicus is adequately described 

 by Hudinaga as summarized by Pearson (1939). 

 Development in P. dvornrum may be similar, since 

 conditions under wjiich the eggs of the two species 

 of shrimp were reared and development subse- 

 quent to hatching are comparable. Photomicro- 

 graphs of several stages of viable eggs were made 

 (fijr.2). 



Hatching was observed by the author in tlie 

 laboratoi"y. At water temperatures of 27° to 29° 

 C, the nauplius emerges about 13 or 14 houi-s after 

 the eggs are spawned (Hudinaga, 1942) . Prior to 

 its emergence, the nauplius moves its appendages 

 convulsively at short intervals. After the furciil 

 spines puncture the &gg membrane, the nauplius 



583837 0—91 2 



Figure 2. — Photomicrograph of eggs in several stages of 

 development. 



emerges, posterior half first, by pushing against 

 the membrane with the first antennae. Emergence 

 from the egg requires 2 to 3 minutes. 



FIRST NAUPLIUS 



Individuals of the first nauplial stage (fig. 3) 

 ranged from 0.35 to 0.40 mm. in body length. 

 Their greatest body width was from 0.18 to 0.20 

 mm. Body lengtli was measured from the anterior 

 to the posterior end exclusive of the furcal spines. 

 Greatest body width between the lateral margins 

 was measured doi"sally and occurred at a ]ioint 

 between the first two pairs of appendages. De- 

 scription of tiie first nauplius is based on 13 speci- 

 mens raised from eggs. 



Tlie nauplius is yellow brown in color and 

 opaque, tlie opaqueness being more pronounced in 

 preserved specimens. Viewed dorsally the body 

 is pear-shaped, the anterioi- part being the wider. 



