(Barrett and McAndrew, 1858)
Body centro-dorsal conical, with cirrus-sockets arranged. Number of cirri 20-30, with ca. 40-50 joints; on the proximnal part the joints are about twice as long as broad, in the distal part they are only about as long as broad, at most one-third longer than broad, and have the distal dorsal edge somewhat swollen, so that the dorsal profile of the cirri is slightlky scalloped.
The cirri, on the whole, somewhat stouter in the distal part.
The first two pennules with ca. 20 segments, the stouter ones slender, elongated. Colour in life green, fades in alcohol to a pale brown.
Pentacrinoid stage unknown.
No specific information. In the British waters the species is abundantly found at the Minch, Skye and off the north coast of Scotland and off S.W. Ireland at depths of 70-100 m.
Northern parts of the North Sea. North coast of Scotland, West Ireland. Southwards it extends to West Iberia, western parts of the Mediterranean, Madeira, southern border of Morocco and the Canary Islands.
Known to have a bathrymetrical distribution, 46-1279 metres.
The genus Leptometra A.H. Clark, 1908, is quite similar to the genus Poliometra A.H. Clark, 1923, from which it differs mainly in the relative length of the oral pinnules, the two first being equally long and markedly longer than pinnule 3. Another important difference is found in the size of the cavity of the centro-dorsal, which is much larger in Poliometra than in Leptometra.
Another spoecies, Leptometra phalangium Joh. Müller, 1841, occurs in the Mediterranean, but it is also known with certainty from the Atlantic. It is easily distinguished from Leptometra celtica by its more slender cirri; the joints of the distal part are not shorter than the proximal ones, all being about twice as long as broad; also the distal dorsal edge of the joints is not swollen.