October 13, 1916] 



SCIENCE 



545 



tion given by Kuschakewitsch. 6 He found in 

 the eggs of a prosobranch, Aporrhais, twenty 

 minutes after fertilization, an oligopyrene sper- 

 mium besides a typical one. Even taking it 

 for granted that this is not an accident of sec- 

 tioning, the facts are not yet convincing. 

 And Kuschakewitsch himself is indeed rather 

 skeptical and does not want to draw far-reach- 

 ing conclusions. It might be mentioned that 

 we had formulated a hypothesis 7 of sex-deter- 

 mination on the basis of such a process which, 

 however, we have since abandoned. The latest 

 work on these questions, by Reinke (I. c.) 

 finally reached one positive, but rather dis- 

 couraging result. He finds in Strombus that 

 the atypical spermatozoa never reach the re- 

 ceptaculum seminis but degenerate and are 

 surrounded by a capsule. The simultaneous 

 work of von Kemnitz 8 also failed to attain 

 positive results, although the fact is of inter- 

 est that the hermaphroditic prosobranch 

 Valvata exhibits no dimorphism of sperma- 

 tozoa. 



As far as we know, only once has a real ex- 

 periment been performed to test the function 

 of the apyrene spermatozoa. K. Hertwig 9 

 started from the hypothesis that fertilization 

 with apyrene spermia is comparable to the 

 parthenogenesis and produces males. There- 

 fore he crossed two species of moth, Pygaera 

 anachoreta and curtula, which are known to 

 produce apyrene spermia. If fertilization 

 could occur by these latter sex-cells, the off- 

 spring, supposedly the males, ought to exhibit 

 only maternal characters. The results were 

 entirely negative, both sexes in Fj being in- 

 termediate in regard to the characters of the 

 parental species. 



« Kuschakewitsch, S., ' ' Zur Kenntnis der soge- 

 nannten wurmformigen Spermien der Proso- 

 branehier, " A nat. Anz., 37, 1910. 



i Goldsehmidt, B., ' ' Kleine Beobachtungen und 

 Ideen zur Zellenlehre, " I., Arch. Zellforschg., 

 1910. 



8 V. Kemnitz, G., ' ' Beitrage zur Kenntnis des 

 Spermatozoendimorphismus, " Arch. Zellf., 12, 

 1914. 



o Hertwig, B., ' ' TJeber den derzeitigen Stand 

 des Sexualitaetsproblems, etc.," Biol. Centrbl., 

 32, 1912. 



We are now able to state a few experimental 

 facts in regard to the apyrene spermia of 

 moths which have been noticed in connection 

 with some other work. The first question is 

 are the apyrene spermia able to fertilize an 

 ovum or to cause development? Some answer 

 is given by the following facts. In my ex- 

 periments on intersexuality in the gipsy- 

 moth an almost complete series of intersexual 

 males was produced in 1915 showing every 

 stage from a male to a female. Now up to a 

 certain degree of intersexuality these indi- 

 viduals behave sexually like males and succeed 

 in mating with the females. For many years 

 we have known that such intersexual males of 

 a low grade are completely fertile, and the 

 eggs fertilized by them develop normally. It 

 was of course of extreme importance for our 

 work to breed offspring from the higher 

 grades of intersexual males and they were 

 therefore all mated, obviously to the limiting 

 type, which was still male enough to perform 

 the mating. All matings were certainly nor- 

 mal, as every female laid a normal egg sponge, 

 which is only done after a successful mating. 

 From the eggs fertilized by low-grade inter- 

 sexual males the normal percentage of caterpil- 

 lars hatched, as in previous years. But from 

 egg batches, fertilized by somewhat higher in- 

 tersexual males, only a few caterpillars hatched, 

 the rest of the eggs being unfertilized. The 

 numbers were for four cultures 3, 3, 2, 3 

 caterpillars, the egg batches containing be- 

 tween 100 and 300 eggs. Finally, in the egg 

 batches laid after mating with the highest 

 type of intersexual male, which was still able 

 to mate, not a single egg developed. Now in 

 studying the sex glands of these males we 

 found that in low grade intersexuality they 

 contained normal sperm bundles, but in the 

 higher forms of intersexuality the entire 

 gonad was filled with giant bundles of apyrene 

 spermatozoa. The intermediate forms, which 

 gave a few fertile eggs, were unfortunately not 

 examined. We think it not unsafe to con- 

 clude from these facts that apyrene spermato- 

 zoa can not induce development, even if they 

 enter the eggs, which, however, also seems im- 

 probable. 



