380 MALMGRENIA CASTANEA. 



prominence, posterior in front of collar. Median tentacle of moderate length, smooth, 

 as are also the lateral tentacles, tentacular cirri and palpi, which are of moderate length. 

 Body about § inch long, of thirty-six to forty-one segments, with madder-brown pigment 

 posteriorly on the dorsum, and more sparingly on the ventral surface. Segmental 

 eminences fairly developed, but without evident papillse. Scales, fifteen pairs, adherent, 

 smooth, with the exception of a small and somewhat triangular group of papillse at the 

 anterior curve in those of a reniform shape ; variously bordered with madder-brown. 

 Dorsal bristles translucent, somewhat short, slightly curved, little tapered, and with a 

 rather abrupt point; spinous rows faint. Ventral bristles translucent, with short spinous 

 regions ; fine rows of spines, a well-marked hook at the tip and a secondary process after 

 an interval. 



Synonyms. 



1868. Eunoa. Report Brit. Assoc, 1868, p. 337. 



1876. Malmgrenia castanea, Mcintosh. Trans. Zool. Soc, ix, 376, pi. lxvii, f. 15 — 19. 



1886. Malmgrenia castanea, Harvey-Gibson. Verm. Liverp., 149 and 345. 



„ Lsenilla castanea, Giard. Bull. Sc. Nord, i, 3. 

 1891. Polynoe (Malmgrenia) castanea, Hornell. Op. cit v p. 235. 



Habitat. — Dredged by Dr. Gwyn Jeffreys off North Unst, Shetland, in 1867, in 

 90 and 96 fathoms, on Spatangus purpureas, and again in 1868, attached near the 

 mouth of the same Echinoderm, living on a bottom of shell-sand in 85 fathoms, twenty- 

 five miles north-north-east of Unst. The same veteran explorer of our seas found it in 

 80 — 125 fathoms, fifty miles west of Valencia, and in 110 fathoms, thirty miles west of 

 the Blasquet, south-west Ireland, in 1870. It was also dredged off St. Peter Port, 

 Guernsey, in 5—7 fathoms, in 1868. Mr. Hornell procured a few on the same host 

 in the Liverpool district in 20 — 22 fathoms, and Professor Herdman at the Isle of 

 Man. The Royal Irish Academy's Expedition of 1886 also procured a small example 

 in 480 fathoms. Professor Giard found it on the shores of France on the same 

 Echinoderm. 



Head (Plate XXVIII, fig. 15) somewhat like that of Lepidonotus and Halosydna in 

 so far as the anterior border of the head runs into the base of the lateral tentacles. The 

 head is pyriform, broad and rounded behind, and narrowed in front. A pair of large 

 eyes lie in front of the nuchal collar, and a still larger anterior pair in front of the 

 lateral prominence, looking forward and outward. They are thus separated by a 

 considerable interval, and in the preparations nearly occupy the corners of a square. A 

 trace of a lens appears in the centre of the anterior pair, which are only partially visible 

 from the dorsum. The smooth median tentacle is moderately developed, and has a slight 

 swelling below the tapering tip (in spirit). The lateral tentacles are short and subulate, 

 with brownish pigment above the base. The palpi are smooth and of moderate length. 

 The tentacular cirri have a similar structure to the tentacle, most being somewhat 

 fusiform in outline. 



Body about f inch in length, and having from thirty-six to forty-one bristled 

 segments. In most of the preparations it is pale anteriorly, but marked with madder- 

 brown pigment on the posterior segments. The colour varies considerably. The 



