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XVIII. On the Radiata of the Eastern Mediterranean. Part I., Ophiuridae. 

 By Edward Forbes, Esq., F.L.S., Professor of Botany in King's College, 

 London. 



Read March 21st, and June 6th, 1843. 



During my late researches in the yEgean Sea I found ten species of Star- 

 fishes, of the order Ophiuridce, several of which are uudescribed. Of these, 

 and of the other Echinodermata met with during my voyage, I propose, should 

 it be the pleasure of the Society, to give a detailed account, and in the present 

 communication I will commence with describing such as belong to the genus 

 Ophiura and to an allied genus hitherto uncharacterized. The animal on 

 which 1 have founded the genus Pectinura (from ttIkw pecto, and oiipa cauda), 

 is a small starfish which came up in the dredge from 100 fathoms water on 

 the coast of Lycia, where it lives among corallines, millepores and brachio- 

 podous moUusca. Its disc is one-tenth of an inch across, flat, and covered 

 with imbricated scales, which, however, are entirely hidden by a clothing of 

 minute granules, these granules being transformed spines, The pair of scales 

 seen on the disc of all Ophiurce are in this species extremely indistinct, or 

 rather are so like their neighbours, that it is with difficulty we can distinguish 

 them. The rays themselves spring from the disc, and some of the scales of 

 the disc ovei'lap their sides. They are short, as compared with the disc ; but 

 in consequence of their being broken away towards their extremities in the 

 only specimen I possess, I cannot state their positive length. They are covered 

 above with scales, which are somewhat orbicular in form, and lap slightly over 

 one another. Beneath, the scales are triangular, or rather fan-shaped, and 

 have their sides encroached upon by the lateral ray-plates, which are squa- 

 mose, and bear on their superior margins seven or eight spines of unequal 

 lengths, but mostly as long as the ray is broad. These spines are smooth. On 

 the under surface of the bodies the ovarian plates, which are seen separating 

 the origins of the rays, are small and transversely oblong. Each bears a small 



