40 THE AMERICAN ARBACIA 



the Fish Commission wharf (Verrill and Smith, 1874; Clark, 1902; 

 Sumner, Osburn, and Cole, 191 1; Allee, 1919, 1923 a, b, c). 



In more recent years, they have been obtained off Naushon Island, 

 Hadley Harbor, Lackey's Bay, Tarpauhn Cove, and off Nobska. They 

 disappeared from Nobska about 1937, and later from other beds, until 

 in 1^48-1950 they were obtained from only two beds. Lackey's Bay 

 and Tarpaulin Cove, and here too they were becoming scarce. The 

 scarcity of the urchins became so serious that a survey of the whole 

 Woods Hole area was made in the summer of 1950 in an effort to 

 discover new beds, under the direction of J. S. Rankin Jr., the Summer 

 Naturalist at the M. B. L, For a period of six weeks, only one Arbacia 

 was found, at Cotuit. Then in September, 1950, a good bed was found 

 on Martha's Vineyard between Menemsha Bight and Gay Head. Un- 

 like the other beds, this bed had small as well as large urchins, and has 

 subsequently become a source of supply, though they are difficult to 

 collect and many are too small for experimental work. 



In 1 95 1, while exploring further afield, many beds were found on 

 the south-east coast of Fisher's Island, off the south coast of Connec- 

 ticut. These urchins were of all sizes, young ones as well as large ones. 

 Unfortunately the distance from Woods Hole (62 miles) necessitates a 

 two-day trip, often hampered by bad weather, but it is another source 

 of supply o{ Arbacia. Also, in 1954, Arbacia were found near the "old 

 Nobska" bed, having returned there after an absence of 17 years. 



Some of the old beds which have been unproductive for some years 

 have now been stocked with urchins, young and old from the newer 

 beds, in the hope that they may again furnish many urchins in the 

 future. 



3. - Quantities Used 



Arbacia punctulata are found in shallow water and at depths down to 

 700 ft. They are obtained by dredging in water 20-90 ft. deep, usually 

 with a tangle. The associations in which they are found around Woods 

 Hole have been studied by Allee (1923 a, b). 



In an ordinary summer, ten or twenty years ago, 20,000-25,000 

 animals were used at the Marine Biological Laboratory. The greatest 

 number used in one summer (1933) was approximately 70,000. The 

 table below shows the decrease in numbers used, in the last twenty 

 years. In 1947, 45,000 were delivered to 18 investigators. In 1948, 

 15,000 were delivered to 20 investigators; 50,000 were ordered. In 

 1949, only 4,000 were delivered and in 1950 only 3,000. The following 

 table is taken mostly from the report for 1950 of J. S. Rankin, Jr. 



