Function of the Labral Glands in Chirocephalus

Abstract

MISS NICHOLSON and Prof. Yonge, in their letter in NATURE of October 12, claim to have obtained experimentally the same results that I described¹ from the study of sections of fixed material of the Fairy shrimp, Chirocephalus diaphanus. They maintain that they have demonstrated that what I described as the coagulated labral gland secretion is, in fact, the contents of the gut regurgitated as a result of the action of the fixative. But what are the facts? They fed an animal on carmine and then fixed, or rather, killed it, by placing it in a solution of Bouin, and observed that during this process its gut showed a periodic antiperistalsis by which the gut was emptied through the mouth. Now while Bouin is an excellent fixative for isolated pieces of tissue, it is a very bad fixative for an active animal of the size of Chirocephalus as it takes far too long to act. I tested it last week and found that one specimen was wriggling violently after a minute, and even after two minutes was still jerking its half-dead limbs. Is it surprising therefore if, during its death struggle, it vomits ?