158 PISTA CKISTATA. 



the British Pista cristata, 0. F. Midler, and of the latter Eupista Darwini, Mcintosh, 

 dredged by the " Challenger" in the Pacific. The forthcoming treatise on the annelids 

 of the " Siboga " expedition by this accomplished author will be full of interest. 



Hessle (1917) arranged the Terebellidas so that this genus followed Trichobranchus 

 and Terebellides, on the ground that it, too, had anterior hooks with long shafts, but in 

 other groups, such as the Polycirridea and Maldanidse (e. g. Rkodine), there is a tendency 

 to a similar condition, so that it appears to be unnecessary at present to break up the old 

 arrangement. 



1. Pista cristata, 0. F. Miiller, 1776. Plate CXIX, figs. 9 and 9 a — body and valvular 

 end of tube ; Plate CXXVa, figs. 8 — 8 c" — bristles and hooks. 



Specific Characters. — Cephalic plate with a thick dorsal collar without eyes (in 

 preparations). Anterior fold often symmetrically sinuous. Tentacles of moderate length 

 and grooved. Body 120 — 150 mm. long, rounded dorsally, with twelve (Marenzeller gives 

 seventeen, about twenty, Hessle) ventral shields anteriorly with reddish margins, and a 

 deep groove throughout the rest of its extent, moderately enlarged anteriorly, and 

 tapering posteriorly to a slender tail with a valvular anus at the tip. Papillae in segments 

 6 and 7 behind the setigerous process. Segments 2, 3 and 4 with lateral lappets. Body 

 of a uniform reddish orange, with a deep orange bar at each scute inferiorly. Lips reddish 

 and the tentacles pale orange. A deep red patch occurs at the anterior part of the second 

 region. The continental examples are greyish-red or brownish-red anteriorly, yellowish- 

 grey posteriorly. Two branchiae with long stems, much and dichotomously divided 

 filaments, forming a dense and whorled bush. They arise from the anterior border 

 of the fourth segment. Seventeen pairs of setigerous processes, which in front 

 converge towards the dorsal median line. Hook-rows double from the eleventh to 

 the twentieth segment (Marenzeller), and the tori are cinnamon-coloured. Hooks with 

 a main fang and three or four teeth above it in lateral view, and with long shafts as in 

 the Lanicides. 



Synonyms. 



1776. Amphitrite cristata, 0. F. Miiller. Zool. Dan. Prod., p. 216, No. 2620. 



1788. „ „ idem. Zool. Danie., vol. ii, p. 40, Tab. lxx. 



„ „ „ LinnaBus. Syst. Nat., p. 3111. 



1789-92. Terebella „ Bruguiere. Encycl. Method., pi. lvii, figs. 1—4. 



1806. Amphitrite „ Turton's Linn., iv, p. 83. 



1808. Amphiro „ Montagu. MS. vol. Linn. Soc, pi. xl, fig. 2. 



1812. Amphitrite „ Gmelin. Syst. Nat., i, pt. vi, p. 3111. 



1818. Terebella „ Lamarck. Anim. s. Vert., t. v, p. 353. 



1820. „ „ Savigny. Syst. Annel., p. 87. 



1828. „ „ De Blainville. Diet. Sc. nat., t. lvii, p. 438, pi. v, fig. 2. 



1830. Amphitrite „ Bose. Hist. Vers., 2nd edit., vol. i, p. 194. 



1836. Terebella „ Templeton. Mag. Nat. Hist., ix, p. 233. 



1840. „ „ Grube. Actin. Echin. u. Wiirmer, p. 65. 



