CHAETOGNATHA, WITH A NOTE ON THE VARIATION AND DISTRIBUTION OF THE GROUP. By Leonard Doncaster, B.A., Scholar of Kings College, Cambridge. (With Plate XIII, and Text-figures 39 and 40.) Among the pelagic organisms, collected by Mr Stanley Gardiner's Expedition in the Maldive Ai'chipelago in the years 1899 and 1900, were considerable numbers of Chaetognatha. They were fished chiefly at night, in moderate depths, and were preserved directly in 4 per cent, formalin. They are divided into two parts, \iz. some were collected between Dec. 10 and Jan. 10, and the rest in April. Those obtained in the winter were much more abundant both in individuals and species, the number of specimens submitted to me being about 900 in the winter months compared with rather over 2.50 in April. In classifying the gi'oup I have followed Langerhans (" Wurmfauna von Madeira," Zeitsclir. wiss. Zool. Bd. XXXIV. p. 132, 1880) and Strodtmann (" Systematik der Chaetognathen," Archiv Naturgeschichte, Jahrgang 58, Bd. i. p. 333, 1892), and have used the names Sagitta, Spadella and Krohnia in the sense which they have defined, viz. Sagitta forms with two paii-s of lateral fins, and two rows of teeth : Spadella with one pair of lateral fins on the tail segment only, and two rows of teeth : Krohnia with one pair of lateral fins extending on the trunk and tail, and one row of teeth. The Chaetognatha fi-om the Maldives include several species well known fi-om European watei-s, and othei-s which have been procured only from the American coast or fi-om Japan, but a considerable proportion (6 species out of 15) appear to be undescribed. Sagitta is much the most abundant genus, but Spadella is represented by one moderately common species, while only two specimens of Krohnia were found. In a Note at the end of the " List of the Species " I have added the description of a new species, found by the late Mr F. P. Bedford at Singapore. 27—2
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