Immature Nematodes of the Genus Contracaecum Railliet and Henry, 1912, from Shrimps

Abstract

Because of widespread collection stations, extending from North Carolina, throughout the Caribbean area and the Gulf of Mexico, to Central America and involving many collectors, it was necessary to preserve most of the host material. This material was preserved in 10 per cent formalin. Nematodes dissected from the host material were cleared in glycerine and mounted in glycerine jelly. In some cases live shrimps from Florida coastal waters were obtained. Viable nematodes found in these specimens were killed in hot 70 per cent alcohol with 1 per cent glycerine added, cleared in glycerine and mounted in glycerine jelly. Specimens treated in this manner were far superior for microscopic examination to those removed from shrimps killed in 10 per cent formalin. Acknowledgments are again extended to the many individuals who obtained shrimp samples for us (see Hutton et al., op. cit.). Also, we would like to acknowledge the help of Dr. Satyu Yamaguti who read the manuscript and offered valuable suggestions. Two thousand thirty-five shrimps [1,306 Penaeus duorarum, 354 P. setiferus, 281 P. aztecus, 5 P. brasiliensis Latreille, 22 Trachypeneus constrictus (Stimpson), 16 T. similis (Smith), 28 Xiphopeneus kroyeri (Heller), 9 Sicyonia dorsalis Kingsley,