FAMILY SPHiEEOMIDiE. 69 On the Propagation, Structure, and Classification of the Family Sphaeromidae. By H. J. Hansen, Ph.D., F.I?I.I..S. With Plate 7. I. Introductory Remarks. Three years ago H. F. Moore ("Rep. Porto Rican Isopoda/' in 'U. S. Fisli Comm. Ball/ for 1900, vol. ii, p. 172, 1901) wrote on tlie Sphjeromidae : "No attempt is made to furnish a key to the genera, owing to the extreme confusion that exists in this family, and it is doubtful if the following two species are properly assigned generically. The dissimilarity of the sexes has frequently misled authors into placing them in widely separated genera, and, while this has not been done in the present case, the limitations of the genera are so indefinitely established that the author has not been able to satisfy himself of the generic affinities of the species described." It may be added that Moore, in reality, refers both his species to genera to which they do not belong. But his critical remarks quoted are correct, and convey an idea on the state of things ; other authors have complained in a rather similar way, and the extreme difficulty in arriving at some clearness has probably been felt by every carcinologist who has attempted to name or describe a number of animals belonging to the family Sphaeromidae. During a stay in Messina and Siracusa in 1893 I collected
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