10 



3. Chirothrips hamatus, Tryb.(?) 

 Tauria: Ssympheropol (25. April 1902, in Apfelbaumblüten), 

 Kamysch-Burun (17. April 1901, in Pfirsiclibaumblüten). 



Subordo Tubulifera. 



4. Anthothrips aeuleatus, Fabr. (= Drepanothrips viticola, Mokrz.) 



Tauria: Koktebel (11. Mai 1906, auf dem Weizen), Pestschanoe 

 (8. Mai 1906, auch da), Kadykoi (13. Mai 1906, auch da), Burkut 

 (24. Mai 1901, auch da). 



Kaukasus: Novorossiisk: Schirokaja balka (11. April 1901), auf 

 den Trauben. 



5. Anthothrips statices Hai. 



Tauria: Melitopolkreise (Mai 1894, auf dem Weizen), Tschirik 

 [Perekopskreise (Juli 1905)]. 



Odessa, 22. April 1907. 



5. The gonad in certain species of chitons. 



By Harold Heath, 

 Leland Stanford University, California, U. S. A. 



eingeg. 10. Mai 1907. 



In 1851 Middendorf 1 discovered what he considered to be evi- 

 dences of a hermaphroditic condition in the chiton, Aniicula pcdlasi; but 

 more recently Plate (1899) ^ working on the same species failed to find 

 any trace of such a condition, and considered (1. c. p. 463) that the first 

 named author was led astray through interpreting sperm mother cells 

 as immature ova. With this one remotely possible exception all known 

 chitons are reported to be dioecious. While working on the development 

 of Trachyderrnon raymondi, a fairly common chiton on the west coast 

 of the United States, I have found this species to be normally herma- 

 phroditic. In the early stages ova appear in typical fashion, but about 

 the time the animal becomes half grown, that is when it is four or five 

 millimeters long, some of the primitive sex cells on the wall of the gonad 

 commence to divide rapidly and ultimately form small clusters (0,065 mm 

 in diameter) of spermatozoa among the neighbouring ova. There is no 

 definite seat of development as in the solenogastres (Neomeniidae) ; the 

 sperms arise at any point on the inner surface of the gland from the 

 anterior to the posterior end. The number of spermatozoa is always 



1 Middendorff, Th., Reise in den äußersten Norden und Osten Sibiriens. 

 Zool. V. Teil 2. S. 163—174. 



2 Plate, L., Die Anatomie und Phylogenie der Chitonen. Zool. Jahrb. Suppl. 

 Bd. V (Fauna Chilensis;. Teil C. S. 330. 



