ON THE DEVELOPMENT OF LINGULA ANATINA. 



II. DISCHARGE OF THE SEXUAL ELEMENTS. 



The mode in which the sexual elements are discharged is 

 descrihed at ' great length in Terebratulina seplentriofialis Couth, 

 by Mokse ('73). I have found another short account of ovulation 

 by Wilson in Whitman's ('85) work on microscopical technique 

 (p. 136). Other writers on the Brachiopod are silent on its 

 breeding habits, though Kowalevsky, Joubin, et al. must have 

 been familiar with them. My notes from personal observations 

 on the emission of eggs and sperm in Lingula may, therefore, 

 not be wholly superfluous. 



In the summer of 1899 when I was staying at the station, 

 I collected a number of Lingula on July 24th and kept them 

 in two large bowls. I had then little hope of securing eggs and 

 embryos, since similar efforts had been made in vain by many 

 of my predecessors. About ten of the specimens were of the 

 maximum size for that locality, and many others were the 

 medium ones, the remaining few being very young. Natural 

 conditions were as far as possible imitated. The mud in the 

 bowls was brought from the same mud flat where the individuals 

 were collected. The water was almost all drawn off by means of 

 a siphon once or twice a day, and the bowls were gradually filled 

 up with freshly drawn sea water containing ample food. There was 

 thus caused an artificial ebb and flood tide. The specimens thus 

 kept appeared in an excellent condition protruding from their 

 burrows the anterior edge of the mantle which appeared drawn 

 out into the form of three funnels arranged side by side. Several 

 days passed without any change. 



Early in the morning of the fifth day i.e. at about 6 a.m. 



