BANSE: REDESCRIPTIONS OF SOME SPECIES OF CHONE AND EUCHONE 



a A 



500/<: d; 50/.: e-h, j 



Figure 10. — Euchone mbrocincta; b-h from syntypes, a and i from NMI, j from South- 

 ward's material: a, end of representative radiole. Broken line indicates extent of flange 

 in syntypes (see also text) ; b, dorsal view of anterior end, branchial crown omitted; 

 c, ventral view of anterior end, branchial crown omitted, after staining. Slightly sche- 

 matic; X indicates the extent of the incision of the ventral shield on the first setiger of 

 E. elegans; d, part of lateral body wall of second setiger, seen slightly from below and 

 behind, with setae and glandular girdle; e, f, bayonet-type and two subspatulate setae 

 from fifth thoracic setiger; g, anterior abdominal uncini (seventh abdominal setiger). 

 Accessory teeth schematic; h, uncinusfrom depression segment (17th abdominal setiger) ; 

 i, subspatulate and limbate setae from sixth thoracic setiger; j, uncinus from seventh 

 abdominal setiger. 



1914) . NMI 77.1908, 1 specimen from each sta- 

 tion. 



Irish Sea, station 22 of Southward (1956, 

 1957) . Dr. E. C. Southward's private collection. 

 3 specimens. 



AdditioTis to the Description: The largest of 

 the well-preserved syntypes, a fairly relaxed 

 specimen, is approximately 2.5 cm long of which 

 about one-fourth is contributed by the branchial 

 crown. The width is about 2 mm. The other 

 syntypes are approximately two-thirds as long; 

 in one of them, a mature female, the branchial 

 crown contributes about one-third of the total 

 length, in the other one it is lost. 



The branchial crowns of the two complete 

 specimens consist of 10 and 13 pairs of radioles 

 with pinnules and up to 8 pairs of slender naked 

 ventral filaments. Two to three pairs of the 

 latter are very short, and one or two pairs are 

 as long as the radioles. The radioles are united 

 for about half their length by a conspicuous 

 palmate membrane. They end in bare tips, prox- 

 imally broad owing to the continuation of the 

 palmate membrane, but narrow in the terminal 

 sections. The latter tend to be shorter ven- 

 trally than dorsally and are, on the average, 

 about half as long in the syntypes as in the ma- 

 terial from northwestern Ireland (Figure 10a). 

 The length of the sections of the radioles free 

 of pinnules is very approximately one-eighth of 



485 



