Zoologist Studies Sense Organs In Crustacea

Press, Volume CIII, Issue 30401, 28 March 1964, Page 15

Zoologist Studies Sense Organs In Crustacea

Sense organs, called stretch receptors, which occur in Crustacea, were studied by Dr. R. L. C. Pilgrim, reader in zoology at the University of Canterbury, during refresher leave in England. These organs signal to the central nervous system the state of stretch or- tension which is applied to various muscles hi the body as,the appropriate joint is moved. They, function like an Engineer’s strain gauge and monitor the position Of the movable parts of the body. Refinements in. some of the more specialised ” of th.ese organs .also show bow rapidly the new position of a joint is taken up and thus . act in a dynamic manner. “Organs with this kind of function are . not confined -to Crustacea but are common in many groups of animals, including man,” said Dr. Pilgrim. His . interest jn the Crustacea seqse organs lay partly in the fact that, they were very much simpler in .construction and more accessible to the investigator for experimental work. In some laboratories they had become widely used in the determination of fundamental behavioural reactions of the nervpus system. ’.

“These data,” said Dr. Pil-. grim, “can be extrapolated to many, if not most, Thus any advances in the general study of these organs may have much wider application than how they operate in Crustacea.” Dr. Pilgrim is also interested in elucidating the properties and distribution of these organs' in a great variety of animals , included in the term, Crustacea. Besides crayfishes and lobsters (which have Bden subjects .of most of this research) he has been studying crabs of many kinds, shrimps, prawns, krill and re* lated animals which, have no well-known name. to study all these Dr.- Pilgrim thus went, for instance, to Plymouth for large “edible

Crabs,” . hermit crabs, and krill, and to. Naples for a large “mantis-shrimp.’.’ Two Matji Results

From all these researches, Dr. Pilgrim produces two main lines of results.

Edible crabs, he said, were known to be vefy much more advanced in. evolution, than crayfishes and their anatomy was so modified that their stretch-receptor organs were expected to have degenerated, along with the profound reduction of the abdomen br tail. ■ “It was a surprise, therefore, to find that the abdomen of the so-called higher crabs Still possess fully-functional sense organs* of the same nature as those in crayfishes. It would.seem that the information .which these organs mediate to the-central nervous system is so fundamental-that it is not lost.in the eburse of evolution so long ' as . even a vestige- of that part of the body femains.” , The other main- line of re* search was in the’ opposite direction: .- to Investigate a crustacean, regarded as much more lowly • in evolutionary progress. Tins was the “man-tis-shrimp,” found small in New Zealand waters but used as a Staple food in the Mediterranean. Dr. Pilgrim said this animal. Showed a more extensive series' of the same ■type of stretch - receptors ■ as in crayfish.

Dr. Pilgrim worked at the Plymouth laboratory of ', the Marine Biological Association of the United Kingdom, the first and still the most important of that country, with a staff of 100 (including three boat crews), an outstanding research record, magnificent library, and excellent research facilities; and the Statione Zoologies, founded in Naples by Germans in 1870 and taken over by the Italians after World War I; It is one of the best in-Europe, with an international staff.