Steiner: Intersexes in Nematodes 



53 



LMmr 



TWO VIEWS OF A HIGHLY INTERSEXUAL FEMALE 



Figure 8. This female has a double set of male spicula (sp 1-4). Three are normal in 

 shape, and the fourth is represented by a spherical body. Notice that there are much fewer 

 papillae than in the female shown in Figure 7. These intersexes are probably due to natural 

 crossing of distinct races or closely related species, as were the intersexes of the gypsy moth 

 produced artificially by Goldschmidt. Left, lateral view ; right, ventra-submedial view ; /, 

 fat body; $ ppl, male papilla; sp 1, spiculum of the left side; sp 3, second spiculum of the 

 right side; sp 4, globular second spiculum of the left side; burs muse, bursal muscle. 



equal length and thickness with the 

 sheaths well developed, hut the muscles 

 around the spicula were not as strong 

 as in the true male. However, the 

 hursal muscles, the rows of male pa- 

 pillae, and even the general form of 

 the tail end was exactly like the normal 

 male. But there was no trace of 

 male gonads and ducts. Very interest- 

 ing it seems to me is Meissner's state- 

 ment that in the intersexual females 

 the eggs were, though normal, some- 

 what smaller. 



Undoubtedly these intersexes are the 

 most pronounced of this kind hitherto 

 observed in Alermithids. They allow 

 us to construct a comi^lete series of 

 intersexual females with all possible 

 grades between a normal female and 

 a female with complete male secondary 

 sex characters. 



As already stated, nearly every in- 

 vestigator who has studied carefully 



adequate material of Ag. albicans has 

 observed such intersexes. Intersex- 

 uality seems in this species of Aga- 

 mcrmis to be a rather common phe- 

 nomenon. As far as wc knoiv there is 

 no other group of animals knozvn to- 

 day in 7vliicli intersexes are observed 

 in sucJi numbers under natural eondi- 

 tions and normally produced. This 

 seems to be a fact specially to be 

 noted. 



What are the causes of these condi- 

 tions? As yet we do not know, but 

 there are some other facts about Aga- 

 mermis deeaudata and related forms 

 which may indicate where we must 

 look for an explanation. Recently in- 

 tersexes have been produced experi- 

 mentally by several investigators, as by 

 Goldschmidt in Lymantria dispar; by 

 Keilin and Nuttal in Pediculus capitis 

 and P. corporis; by Sexton and Hux- 

 ley in Gammarus clievreuxi and related 



