480 PEOr. p. M. DUNCAN OK SOME 



the scales, whicli are of good size, and the large radial shields are 

 euvironed by rows of small scales as by belts. But the upper 

 arm-plates have also the supplementary rows of small scales 

 around them, and there are also large accessory side pieces. 

 Moreover there are hooks on the side arm-plates. This mixture 

 of Ophiolepian and Ophiopholian characters is very interesting ; 

 and this species, I consider, renders the abolition of Ophioplwlis, 

 as a genus, inevitable. 



Qphionereis duhia is represented by a variety in the Korean 

 collection ; and the distinctions between the variety and the type 

 have been already noticed. 



Opldonereis variegata is allied to the species 0. annulata from 

 Panama, but the arrangement of the side arm-plates,^ of the acces- 

 sory plates, and of the mouth-papillse differs. There is a manifest 

 resemblance to 0. squamata, Kinberg, from Honolulu ; but the 

 shape of the under arm-plates and the arrangement of the radial 

 shields diflfers ; and the resemblance is less to 0. crassispina, Kin- 

 berg, from the same island. 



Amphiura LutJceni has small radial shields touching without, 

 and the side mouth-shields are not joined within. There are 

 four mouth-papillse, two of which are spinous and long, and 

 the inner pair large ; there is but one tentacle-scale, and there 

 are six spines near the disk, and four further out. This does 

 not approach in form bo any as yet described from the Pacific side 

 of America. 



Ampliiura TcorecB has an oral arrangement of mouth-papillge, 

 jaws, and side moiitli-shields remarkably like that of A. sq^uamata, 

 Sars, from the Atlantic and the eastern coast of the United 

 States; but the radial shields diifer, and the mouth-shields also; 

 the arms also differ in length. Lyman states that there is a close 

 resemblance between A. squamata and A. tenera, Liitken, from the 

 "West Indies, and A. pugetana from California. It is interesting 

 to find this afliuity prolonged still further west, in the form of the 

 short-armed species under consideration. 



The genus Hemiplwlis of Agassiz contains AmpJdurcs with the 

 disk naked below ; but to this evident generic attribute he added 

 some which are not of generic value, such as limiting the arm- 

 spines to three and the mouth-papillae to two. In Remipliolis 

 microdiscus the two mouth-papillae near the side mouth-shields 

 are evident enough, but there are two more under the true teeth ; 

 moreover there are four spines. 



