REPORT ON THE HEXACTINLE 



33 



was a single additional pair of this fifth cycle. In the individual 

 with a total of 91 pairs irregularities occurred in only two of 

 the primary interspaces. The fourth cycle was completely de- 

 veloped so that there were 10, 10, 20, 40= 80 pairs of regular 

 mesenteries ; and in addition 1 1 pairs representing a fifth cycle. 

 Eight of these were situated in a primary interspace next one 

 of the directive pairs and alternated in a regular manner with 



D 



the pairs of the older cycles ; the other three occurred in the 

 middle lateral interspace of the other side of the body, one of 

 them intervening between the primary mesenteries on one side 

 of the interspace and the succeeding member of the fourth 

 cycle, while the other two alternated with the fourth cycle pair 

 next the primary pair on the other side of the interspace. Fin- 

 ally in the individual with 104 pairs there are again four cycles 

 regularly developed ; in a primary interspace next one of the 

 Annals N. Y. Acad. Sci., XIV, June 5, 1901 — 3. 



