56 THE AMERICAN ARBACIA 



window technique (1915, p. 127). I have found no evidence of imma- 

 ture or maturing eggs, indicative of a regenerating ovary, either when 

 examined fresh or in sectioned material a week or ten days after forced 

 shedding from animals fully ripe ; the ovaries are full of ripe mature 

 eggs which were obviously not shed when the others were. 



f. Lunar Periodicity (Other Species) 



The idea that sea urchins and other sea animals are full of eggs at the 

 period of full moon was quite generally held by the ancients. Both 

 Aristotle and Pliny expressed this belief, and other classical writers, 

 e.g., Lucilius and St. Augustine (see under Historical). The belief 

 prevailed through the middle ages and is still held by the fishermen 

 around the Mediterranean. No periodicity has been verified by in- 

 vestigators at the Naples Station. However, one of the earliest workers 

 on fertilization of sea urchin eggs, Fol (1879, p. 86), states that in 

 Toxopneustes lividus ( Paracentrotus lividus) and Sphaerechinus brevispinosus 

 (S. granulans) at Messina, the sexual products are liberated each month 

 at full moon, and the animals are then empty for a few days ; there are 

 more of the sexual products in spring and summer than in fall and 

 winter; he says that the fishermen are aware of these facts, since sea 

 urchins are used for the table. There is some evidence that Lytechinus 

 (Toxopneustes) variegatus at Beaufort is ripe at full moon and empty just 

 after (Tennent, 19 10 a, p. 658 footnote) but the evidence of lunar 

 periodicity is not conclusive (Tennent, Gardiner, and Smith, 1931, 

 p. 7). It is said that in Greece the gonads of sea urchins used for food 

 appear on the market only during certain phases of the moon and at 

 other times the animals are spent (Just, 1919, H, p. 17 footnote, quoting 

 Tennent). 



A special study of lunar periodicity vyas made by Fox (1924 a, b) 

 who found that there is a lunar periodicity in the Red Sea form Cen- 

 trechinus (Diadema) setosus at Suez. At full moon during the breeding 

 season, an animal spawns, becomes again full of ripe eggs or sperm at 

 the next full moon. But at nearby Alexandria, there was no perio- 

 dicity in the Mediterranean form Paracentrotus lividus and none in this 

 species at Naples, Marseilles, or Roscoff. Fox is of the opinion that 

 the belief in periodicity spread in ancient times from Suez, where it 

 does occur, to Greece and the Mediterranean countries where it does 

 not occur, and the belief persists to the present day (see also Zirpolo, 

 1929). Mortensen (1937, HI) could not confirm Fox's observations on 

 Diadema setosum, finding that ripe specimens could be obtained irre- 



