Note 12 — Chapter IV · THE MORPHOLOGY OF THE COM­MON CRAY­FISH: THE STRUC­TURE AND THE DE­VEL­OP­MENT OF THE IN­DI­VI­DUAL. (continued 2)

Whether, as some observers state, the hypoblastic cells grow over and inclose the food-yelk or not, is a question that may be left open. I have not been able to satisfy myself of this fact.