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PART II. SYSTEMATIC ACCOUNT 



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rounded metameric papillae (Fig. H9F). Each papilla contains two or three 

 pyriform glands, and the ventral sulcus between them is rather narrow, 

 whereas the dorsal ciliated band, which begins at the front edge of the trunk, 

 is broad (Fig. 149 i?). In the males the slightly protuberant and large genital 

 papillae lie vertically at the front end of the metasoma (Fig. 149^4). The 

 cuticular plaques of the metameric papillae are transversely oval, with dense 

 sickle-shaped thickenings along the front edge, on which may be observed, 

 under sufficiently high magnification, numerous fine striations perpendicular 

 to the edge (Fig. \50A). The plaques are 25/x across. The non-metameric 



part of the preannular section has compara- 

 tively small, scattered papillae, also bearing 

 plaques (Fig. 1505). The latter are hardly 

 different from those of the metameric papil- 

 lae. In the zone of thickened papillae about 

 ten comparatively large, irregularly situated 

 ventral papillae are present. The plaques lying 

 on them are distinguished by very dark, 

 homogeneous bow-shaped thickenings along 

 the front edge (Fig. 150C) and by their 

 smaller size (c. 17-18/x across). The remain- 

 ing part of the trunk in front of the girdles 

 lacks papillae. Two girdles lie one close be- 

 hind the other; both are interrupted on the 

 ventral side and the first on the dorsal side 

 also. The ridges of the girdles are hardly dis- 

 cernible (Fig. 149G, #). The toothed platelets 

 are yellowish, narrow ovals, whose front ends 

 are narrower; they measure 10-13/x long and 

 are arranged in two rows in each girdle 

 (Fig. 1497). The numerous teeth on the 

 surface of the platelets all point forwards and the front group of teeth is 

 almost non-existent. The very long postannular region of the metasoma has 

 characteristic transverse ventral rows of adhesive papillae placed at more or 

 less equal intervals (Fig. 1497), Wlt ^ f° ur or fi ye papillae in each row. The 

 plaques here are transverse rods, bent slightly forward and fringed with a 

 narrow membrane (Fig. 150Z)). These rods are 40-50/x long. 



Nine individuals, a few of which were incomplete, were measured, giving 

 the following figures for the dimensions of the various parts of the body : 

 length of the tentacles, 8-14 mm; the fore-part of the body, 0-8-1-5 mm 



Fig. 1 50. Diplobrachia japonica : 

 A - cuticular plaques from a 

 metameric papilla ; В - cuticular 

 plaques from the non-metameric 

 part of the metasoma; С - the 

 same from the zone of thickened 

 papillae; D - the same from the 

 postannular section of the meta- 

 soma. 



