LERNEAD^E. 321 



That part of the history of the Lerneadae which is 

 connected with their sexual relations and propagation is 

 still involved in much obscurity. But the details we have 

 received from Nordmann and Kroyer, with regard to the 

 males, are no less singular than many of the other curious 

 parts of the history of these animals. By some of the 

 earlier observers it was supposed that those individuals 

 which had not oviferous tubes were males, while others 

 imagined that they were hermaphrodites. Neither of 

 these opinions, however, will stand the test of inquiry. 

 The ovaries of the female, after the eggs have attained 

 maturity, burst and disappear, and thus, as Kroyer ob- 

 serves, " the Lernea which to-day was considered a female, 

 to-morrow might be regarded as a male." In the course 

 of investigating different species of Lerneadas, Nordmann 

 discovered, in several instances, small bodies adhering to 

 the generative organs of the females, which, on closer in- 

 spection, proved to be animals that differed very much in 

 appearance from the female, and, on the contrary, bore 

 considerable resemblance to the young ones in the first 

 stage of their development. These he believed were the 

 males, and though Burmeister has thrown great doubts 

 as to the entire accuracv of Nordmann 's observations, 



f */ 



his statements as to the fact of these animals being males 

 are borne out by Kroyer and others. It is probable, as 

 Nordmann remarks, "that the males and females are 

 mixed together when they come out of the eggs, but that 

 they develope themselves differently at the last change of 

 skin." They continue to show uniformity in regard to 

 the form of the head, and the form and situation of the 

 parts connected with it, but they want the apparatus for 

 attaching themselves which the females possess, having 

 instead, two pairs of strong, hooked feet. They differ 

 constantly in the form of the other parts of the body, and 

 show a remarkable diversity from the female with respect 

 to size, being very much smaller. These males bear a 

 strong resemblance to each other, even in different genera, 

 in which the females are very unlike. This fact and the 



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