The following is the first of a proposed series of systematic papers on the polychaetous annelids of the southeastern United States and West Indian regions. I have collections made by the American Museum expedition in the Bahamas in 1908, in Bermuda by Professor Verrill, to whose generosity I am indebted for an opportunity of studying them, and by myself while at the Laboratory of the Carnegie Institution at the Dry Tortugas. To the Director of this laboratory, Dr. Alfred Goldsborough Mayer, I am under the greatest of obligations for many courtesies, and for the facilities of the laboratory which he put at my disposal.
The majority of the annelids at the Tortugas live in the crevices of the dead coral rock, or in some cases in canals penetrating the solid part of this rock, these canals sometimes fitting the bodies of the animals so closely that they seem to have been excavated by the animals. Tube dwelling forms, as Sabellids and Serpulids, live in or among the heads of the living coral, and in the mud in the moat at Fort Jefferson. There are no mud flats in this region, the annelids usually found in such places living in the dead coral.
To secure satisfactory results in Annelid collecting, preliminary narcotization is essential, and for this purpose I have found a solution of MgSO4, at a strength of 153.74 grams to the litre, gives the best results. This was devised by Dr. Mayer, and used by him for a variety of other animals. When completely narcotized, they are transferred to 5% formalin until dead, and are then fixed in 90% alcohol. It is usually desirable in order to avoid shrinking to run them down to 50% alcohol, returning to 80% for final preservation. This method preserves both form and color very well. Final preservation in formalin is to be avoided, as specimens in it have a tendency to macerate.
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