Winter Journey: 



Ancient Sea Monsters 



From the movies and the late late TV shows we all know 

 what a monster is. It is a hideous creature, often in human- 

 oid form, whose primary occupation seems to be scaring 

 pretty girls. But if we look up the word "monster" in a 

 dictionary, we find that it merely refers to any organism, 

 plant or animal, which is very different in size or other 

 structural feature from the typical members of its kind. The 

 Museum's Winter Journey examines some ancient sea mon- 

 sters in the dictionary sense. 



From our displays of prehistoric marine animals we find 

 many which were of monstrous proportions for their kind. 

 Among the Protozoa, which are generally microscopic, a 

 sfjecies measuring a few inches long would be a giant. So 

 would a two-foot sponge, or a 15-inch brachiopod, or a 

 70-foot crinoid. Many of these monsters were attractive, 

 even beautiful, in shape. And they lived long before there 

 were any pretty girls to frighten anyway. 



Persons expecting something along the lines of the tradi- 

 tional monster will not be entirely disappointed. A skin 

 diver coming face to face with a 15-foot-long Dunkleosteus 

 might well jump right out of his gear. Sea-serpents con- 

 tinue to be reported from time to time. Have the Plesio- 

 saurs, with their long, snake-like necks, survived from the 

 age of dinosaurs to haunt us? Are they the basis for such 

 reports as the Loch Ness monster? Although properly skep- 

 tical, the finding of living coelacanths in 1938 has made 

 scientists cautious about completely dismissing such reports. 



Both scientists and science-fiction writers (the two are 

 often combined in one person) have long explored the pos- 

 sibilities of the dimensional extremes of life. Most people 

 tend to forget that man is close to the extreme in size of most 

 kinds of animals. The names of all larger animals could be 

 written on a single sheet of paper. The names of the smaller 

 forms would occvipy several volumes. There are mechan- 

 ical limits to how large an animal can get. I am six feet 

 tall. A doubling of my height does not stretch the bounds of 

 credibility at first glance. But merely doubling my height 

 would increase my weight eight times. My normal 135 

 pounds would jump to 1,080 pounds, while the area of my 

 bones, which support my body, would be increased only 

 four times. I would be in no condition to do any running 

 or jumping. Even ordinary walking would place me in con- 

 stant jeopardy of breaking my legs. 



Dunkleosteus terrelli was a "sea monster" by any defini- 

 tion of the term. A Placoderm (armored fish), this predator 

 grew to 15 feet and lived in the Devonian Period, about 

 365 million years ago. 



For organisms living under a reduced gravitational force, 

 some of these limitations are removed. It is no accident 

 that the largest creatures that have ever lived are aquatic. 

 The blue whale, which may attain a weight of 120 tons or 

 more, is the largest animal that has ever lived on earth, but 

 is strictly confined to water. The bulkiest dinosaur, Brachi- 

 osaurus, tipped the scales at only some 60 tons, and it prob- 

 ably spent most of its time in fresh-water lakes. For those 

 who delight in speculative reflection, ponder the question 

 of the significance of the fact that man spends the first nine 

 months of his life in an aquatic environment. 



"Ancient Sea Monsters" is Journey number 56 in a 

 series begun in 1955. With the successful completion of 

 each series of four Journeys, boys and girls are awarded a 

 certificate and title: Museum Traveller (four journeys); 

 Museum Adventurer (eight journeys); Museum Explorer 

 (12 journeys). After 16 journeys have been completed the 

 Explorer becomes a Beagler, ready to undertake a special 

 journey which carries him throughout the Museum to study 

 some of the natural history materials observed by Charles 

 Darwin on his famous "Voyage of the Beagle." Successful 

 Beaglers are awarded a certificate making them members of 

 the elite Discoverers Club. 



There is no charge for taking any of the Museum Jour- 

 neys. Copies of the Journey question sheet and further in- 

 formation on the program may be obtained at the Museum 

 entrances. The Winter Journey runs from December 1 to 

 February 28. 



— Ernest Roscoe, Raymond Foundation 



Page 6 DECEMBER 



