446 PART II. SYSTEMATIC ACCOUNT 



2 (1) The crown consists of not more than 100 tentacles of which only 20 

 may be visible from the outside in ventral view. The keels of the 

 bridle do not meet ventrally. The hoop-shaped plaques of the 

 metameric papillae are only 55-75/x across. The tube is transparent 

 and up to 1 -4 mm in diameter. 2. S. beklemischevi (p. 450). 



/. Spirobrachia grandis Ivanov (Figs. 5, Y7F, 18, 59, 170-3) 



Ivanov, 1952: 384-7, 388, Figs. 23-7; Zenkevitch, 1954: 79, 80, Figs. 8, 9; Zenkevitch, 

 Birstein and Belyaev, 1954: 67, 68, Figs. 9, 10; Hartman, 1954: 185; Ivanov, 1954b: 75, 

 77, 79, Figs. 6, 7; Ivanov, 1955e: 225, PI. LXV, Fig. 6; Ivanov, 1956b: 1864, 1868; 

 Ivanov, 1956c: 166, 169; Kirkegaard, 1956b: 186, Fig. 4; Abrikosov, 1957: 238; Beklemi- 

 shev, 1957: 399, Fig. 146; Ivanov, 1957a: 483, 484, 489, 492, 493, 495-7, Fig. 59; Vino- 

 gradova, 1958: 112; Dajoz, 1958: 233, 236, 237, Figs. 3 (incorrectly labelled), 6; Ivanov, 

 1958a: 1369, 1370; Ivanov, 1958b: 1682, 1687, 1688, Figs 3, 7; Ivanov, 1960a: 1530, 

 1538, 1541, 1543, 1546, 1559, 1570, 1576, 1588, 1591, 1606, Figs. 1399, 1400, 1408, 1419, 

 1420, 1422, 1425, 1431, 1439, 1468; Ivanov, 1960c: 6, 10, 12, 22, 27, 30, 57, 61, 75, 76, 91, 

 92, 96, 228, 254-8, 261, 262, 266, Figs. 5, 17, 18, 27, 37, 39, 41, 44, 51, 59, 87, 170-3. 



The fore-part of the body is a little compressed dorso-ventrally. The 

 cephalic lobe is also compressed and is shaped like an equilateral triangle. 

 The keels of the bridle, situated on the surface of cutaneous ridges, run close 

 together on the ventral side, while their dorsal ends fuse. Narrow median 

 furrows run along both the dorsal and the ventral side of the mesosoma 

 (Figs. 5, 170, 1715). The tentacular apparatus consists of very numerous 

 tentacles, and in one specimen, a female, 223 were counted. The whole 

 tentacular plate makes not less than six rather close turns of spire (Figs. \1F, 

 18, 59), and its external free edge is attached to the body considerably farther 

 down than the next turn, thus further emphasizing the asymmetry of the 

 crown. The point of attachment of this edge lies on the right side in the 

 female (Fig. 17Ы) and on the ventral side in the male (Fig. \12A). In both 

 sexes the lophophore begins on the right side of the protosoma with a broad 

 base, pointing forwards, gradually tapering and describing 3-4 turns around 

 the main axis of the body (Fig. 18). Beginning from the outermost free edge 

 of the tentacular plate, ventrally or on the right side of the body, the line of 

 attachment of the tentacles runs first on to the left side, making a half or a 

 little more than a half revolution. Then the tentacles extend on to the base of 

 the lophophore and then on to the lophophore proper, describing a corkscrew 

 on its outer side right up to the tip (Fig. 18). The pinnules are arranged along 

 the inner side of the tentacles in four rows on each. 



The metameric part of the trunk bears a large number of adhesive 



