OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 55 



shields and perhaps also the arrangement of the upper plates of the disk, separate 

 A. latispina from A. Jcinbergiensis. 



A. Icinhergiensis is also near A. Jlexuosa Ljungman, but the latter has brachial 

 spines which are fewer and pointetl, and the mouth shields have a very different 

 shape; there can be no confusion of the two species. 



What differences can bo pointed out between A. I'inhergiends and A. jialmeri? 

 The two species are certainly very much alike, and their affinities are so great that I 

 confused them in 1907, which confusion was not without excuse, owmg to the very 

 vague information we possess regarding the characters of A. imlmeri and to the 

 absence of specimens making a comparison possible. Now that I have studied the 

 type of A. jlexuosa, a species so near A. palmeri that Lyman at first confused these 

 two forms, and have been able to compare A. hinhergiensis with A. latlspina, the 

 characters of the former appear much clearer to me; unfortunately, these com- 

 parisons are incomplete, since I have been unable to study the typo of A. palmeri, 

 which I know only by the draAvings and by a few remarks of Lyman. But it seems 

 to me impossible to unite with an AmpMura having seven and sometimes eight 

 brachial spines, a form with five spines only, these figures occurring on such specimens 

 as have about the same size; and Ljnnan had some examples of A. palmeri iu 

 which the diameter of the disk reached even 6.5 mm. Moreover, the under face of 

 A. palmeri offers some rudimental plates which are completely lacking in A. kin- 

 bergiensis; lastly, the shape of the second and third brachial spmes of my species is 

 not at all as described and figured by Ljonan iu A. palmeri. As regards the 

 external oral papilla, its shape is very different in the two species, if we follow the 

 scheme which L^-man published in 1S75 (75, pl- 5, fig. 68); the indications of the 

 text are much less precise, since the WTiter states only that this ])apilla can scarcely 

 be called "sphiiform," as I stated in 1907. Under these conditions, I thought it 

 necessary to separate the two species. 



AMPHIURA PALMER! Lyman. 



Plate 18, figs. 1 and 3. 



ATbatross, 18S4. Key West, Florida. Two specimens. 



I was very glad to find among the lot of Ophiura^ which were sent to me in 

 1913, one bottle labeled Amphiura palmeri, which was determined by Ljinan. 

 These two samples are quite in conformity with this author's descriptions, and by 

 studying them I have been able to solve a few ciuestions which still remained 

 doubtful and to which I have called attention above, such as, among other things, 

 the characters of the under face of the disk, the shape of the external mouth papilla, 

 and the brachial spines. 



In the best preserved individual, the photograph of which is reproduced on 

 plate 18, figures 1 and 3, the diameter of the disk is 5 mm. and the length of the 

 arms exceeds 40 mm. As may be seen on the photograph, the under face of the 

 disk is beset all over with plates which form a perfectly uninterrupted covering, 

 succeeding without any lack of continuity the plates of the upper face. The 

 under plates are smaller than the latter, but they are nevertheless very easy to 

 distinguish. 



6061°— Bull. 84—14 5 



