THE SPINY LOBSTER OF SOUTHERN FLORIDA. 307 



or issued from the oviducts in a steady stream and were driven backward against the pleo- 

 pods by the beating of the exopodites. Examination under the microscope shows each 

 egg to be stalked, and the stalks of a bunch of eggs are tangled together to form a common 

 stem whose distal end is flattened where it comes into contact with the seta, to which it is 

 fastened. All of the eggs were laid from four to six hours after spawning commenced. 



DEVELOPMENT OF THE EGG. 



The earliest stage in the development of the egg which was seen was that of eight 

 cells. Subsequent stages were observed to the blastula, but the exact time between con- 

 secutive stages is not known, because the eggs died quickly in water under the microscope. 

 Eggs of 16 cells were found in the same lot with eggs of 8 cells, and the inference is that 

 they do not all develop at an equal rate. Some were found which segmented abnormally, 

 the yolk remaining in a solid mass at one pole, while it was segmented at the other pole. 

 The 8-cell stage was not found on the pleopods after 12 hours, and the 16-cell stage was 

 not found after 24 hours. The morula was observed 30 hours after the eggs were known 

 to have been laid and the blastula after 48 hours. These later stages may have been 

 reached at an earlier period in other eggs than those observed. The yolk material of 

 the eggs is dense and opaque, and further study of the embryo was impossible without 

 resorting to sectioning. The eyes of the embryo can be seen after seven days, and exami- 

 nation under the microscope shows that at least five pairs of appendages are developed. 

 Much yolk is present at this time and but little detail can be seen. It is known from 

 observation of three females carrying spawn that the eggs were all hatched in 18 days 

 from the time they were laid. The time probably varies as it does in the development of 

 other eggs, but the maximum time evidently does not exceed three weeks. 



Recently laid eggs are of a bright orange-red color, but as the embryo develops the 

 color changes to clear, light brown, and just before hatching the eggs are almost colorless. 

 This change in color is due to the absorption of the yolk material. It is not difficult, 

 therefore, to judge the approximate age of the eggs by their color and general appearance. 



SIZE AND NUMBER OF EGGS. 



The eggs are quite uniform in size and shape. Eggs which have been recently laid 

 are slightly oval or spheroidal in shape, the major axis measuring 0.5 mm. and the minor 

 axis 0.45 mm., but they become more spherical as the embryo develops. The eggs 

 increase slightly in size and the diameter is about 0.55 mm. just before the larva hatches. 



Several estimates of the number of eggs carried by the female have been made. 

 The number for a female measuring 3% inches, length of carapace, is about 500,000. A 

 larger individual, measuring 4 inches, length of carapace, carried about 700,000 eggs, 

 which seems to be about the maximum number. The eggs measure about 7,500 to the 

 cubic centimeter. 



Practically all of the eggs hatched on females observed, only a small number of dead 

 eggs remaining. The dead eggs were opaque and dull in appearance, and it is possible 

 that they were never fertilized. It is known that mud covering the eggs will cause then- 

 death. It therefore is important that the fifth dactyls of the female remain intact, for 

 it has been shown that these appendages are utilized in keeping the eggs free of sediment. 



