BANSE: REDESCRIPTIONS OF SOME SPECIES OF CHONE AND EUCHONE 



tiger, the rings are invisible after using methyl 

 green, which stains the setigers in question uni- 

 formly except for the inter- and intrasegmental 

 furrows. Posterior to the 15th to 20th abdom- 

 inal setiger, the stain is accepted by numerous, 

 distinct cells arranged in presetal and postsetal 

 bands. These bands coalesce in the posterior 

 part of the abdomen. 



The first bundle of setae, slightly smaller than 

 the following ones, inserts in the collar at the 

 same level as the following notopodia (Figure 

 8c). The notopodia have small lips (Figure 8d) 

 and long limbate, bayonet-type and narrow spat- 

 ulate setae; the latter have pointed tips (Figure 

 8e). The thoracic uncini, with small wings (Fig- 

 ure 8f ) are arranged in single rows. 



Anterior abdominal parapodia have about 30 

 uncini. The large (ontogenetically most recent) 

 uncini (Figure 8g) have squarish bases and 

 three to four rows of four or five coarse teeth. 

 The uncini change gradually within the torus 

 into smaller hooks (Figure 8h) with rounded 

 bases and somewhat more teeth (five on the 

 fourth setiger, seven on the ninth). In the pos- 

 terior abdomen, the smallest uncini of a torus 

 are similar (Figure 8i; about 10 columns of 

 teeth); the largest ones (Figure 8j), however, 

 have very broad posterior portions and crowns 

 with more numerous teeth in approximately half 

 as many rows. 



Juveniles of about 5-mm trunk length and 0.4- 

 to 0.5-mm width, with about 35 abdominal se- 

 tigers, show the white rings clearly. Staining 

 with methyl green, however, indicates that the 

 glandularization of the epidermis is not complete. 

 The dye-absorbing cells are distributed princi- 

 pally along the edges of the stained areas so that 

 the centers of the areas are light. 



Remarks: Chone albocincta seems to be dis- 

 tinguished from all other species of the genus 

 (cf. p. 479) by the whitish segmental rings of 

 tissue. Somewhat similar presetal rings, how- 

 ever, also occur in C. veleronis described above. 

 Neglecting diflferences in size, C. albocincta may 

 be separated from the northeast Pacific species 

 without ventral shields (C. aurantiaca, C. duneri, 

 C. infundihuliforynis, C. magna, C. mollis, and 

 C. veleronis) also by the following: the post- 



setal glandular girdle on the second segment is 

 narrow ventrally (from C. veleronis); the first 

 segment is indistinguishable in the first segment 

 in unstained animals (from C. mollis); the ra- 

 dioles have long free ends (from C. aurantiaca 

 and C. infimdibuliformis) ; the abdominal uncini 

 have coarse teeth (from C. duneri). Chone 

 magna has spatulate setae without pointed tips 

 and only one form of abdominal uncini. 



EUCHONE MALMGREN, 1866 EMENDED 



EUCHONE Malmgren, 1866, p. 405.- Langer- 

 hans, 1881, p. 111.- Saint-Joseph, 1894, p. 250.- 

 Bush, 1904, p. 190.- Hofsommer, 1913, p. 327.- 

 Mclntosh, 1923, p. 281.- Fauvel, 1927, p. 339.- 

 Berkeley and Berkeley, 1952, p. 121.- Ushakov, 

 1955, p. 418.- Day, 1967, p. 774.- Banse, 1970, 

 p. 389. 



Type species: Euchone analis (Kroyer) (cf. 

 Bush, 1904). 



Diagnosis: Sabellidae with semicircular 

 branchial lobes sometimes united by palmate 

 membrane. Collar conspicuous, sometimes bi- 

 lobed. Postsetal girdle of glands on second se- 

 tiger. Ventral shields sometimes present. Anal 

 depression with lateral wings formed by var- 

 iable number of caudal segments. Three types 

 of thoracic notosetae: upper, or upper-anterior 

 ones limbate; lower, anterior ones narrowly lim- 

 bate (bayonet-type) ; and lower, posterior ones 

 spatulate or usually subspatulate. Thoracic 

 neuropodial uncini long-handled, acicular. Ab- 

 dominal notopodial uncini avicular, with rounded 

 or square bases; abdominal neurosetae limbate. 



Remarks: The genus continues to comprise 

 all Fabriciinae with an anal depression. Added 

 to previous diagnoses are presence or absence of 

 the palmate membrane, the note about the collar, 

 the postsetal girdle of glands, the bayonet-type 

 setae, and the ventral shields. The last three 

 characters had previously been mentioned by 

 Banse (1970). It must be noted that E. alicau- 

 data Moore, known so far only from one speci- 

 men, possibly lacks bayonet- type setae (cf. p. 

 489). The number of thoracic setigers (almost 



481 



