The spiny lobster of southern Florida. 305 



GENITAL OPENINGS AND COPULATION. 



GENITAL OPENINGS OF THE MALE. 



The external sexual organs of the male (Fig. 270, opp. p. 295) are located on the 

 greatly enlarged eoxopodites of the fifth pair of legs. The coxopodites extend inward, 

 the inner ends nearly meeting on a median line, and curve anteriorly and outward, the 

 anterior part being compressed into a sharp ridge which is flatly concave on the anterior 

 side. The ventral surfaces of the coxopodites are concave, forming a cup in which the 

 external sexual organs of the male lie. These organs are somewhat pear-shaped and 

 appear in life as suckerlike pads. Each of these pads is provided with a small brush of 

 short setae which project from the anterior side next to the sharp ridges and which are 

 set obliquely to the axis of the coxopodite. The external openings are curved slits 

 protected by thin lips of chitinous material, which are usually kept tightly closed in life. 



GENITAL OPENINGS OF THE FEMALE. 



The external openings of the oviducts (Fig. 271, opp. p. 295) are located on the coxae 

 of the third pair of legs at the articulation of the coxopodites with the sternum. These 

 openings are roughly ovoid in outline, measuring 3.5 mm. on the major axis and 2.0 mm. 

 on the minor axis. The oviducts do not open directly downward, since the anterior 

 margin is somewhat higher than the posterior margin. The opening of the oviduct is 

 protected by a flap of thin chitin which narrows the opening itself to a small pore. 



COPULATION. 



The manner in which copulation is effected has been deduced from observations of 

 spiny lobsters in captivity. The male crawls nimbly about, approaching females ap- 

 proximately his own size. The legs are used to fence in the female, and an attempt is 

 then made to turn her over. Sometimes the female is met head on and forced upward 

 and backward, the second pair of legs being used to hold the female. The female 

 successfully repulsed the male each time during these observations, and coitus did not 

 actually take place, but there seems little doubt that the female is turned over upon its 

 back during copulation. 



One female was observed carrying a seminal vesicle while the shell was still quite 

 soft, showing that copulation evidently had taken place soon after molting. This spiny 

 lobster died, and it was not learned how long the seminal vesicle is carried before spawn 

 ing takes place. Later observations indicated that the sperm is probably carried over 

 winter. 



Observations during two seasons (1918, 1919) were made upon large numbers of 

 spiny lobsters brought into the Key West market during August, September, and 

 October. It was noted that over half of the females which evidently had recently 

 molted were bearing fresh seminal vesicles, which seems to support the belief that 

 mating takes place soon after the female molts. The mating season, judging from these 

 observations, occurs from August to November. 



