240 BULLETIN OF THE 



plate) 1 : .8. Side arm-plates stout and well marked, but not very promi- 

 nent. Upper arm-plates, near base of arm, wider than long, with sharp lat- 

 eral angles, and bounded without by a strong curve, on the sides by 

 re-entering curves converging inwards, and within by a very short line • 

 length to breadth (8th joint) .8 : 1.2. Disk naked below, but the upper sur- 

 face is closely set with short, even, very stout, nearly smooth cylinders hav- 

 ing rounded ends. These cylinders are .5 mm. high, jointed at their base, 

 so that they can lie flat to the disk, and their ends under the microscope are 

 seen to be slightly thorny. Radial shields completely naked, small, sepa- 

 rated partially by a single line of little cylinders; length to breadth 3 : 1.5. 

 Seven stout, gently tapering, blunt, rounded, slightly flattened, nearly 

 smooth arm-spines, which are wholly opaque, and only present feeble termi- 

 nal thorns under the microscope. The two upper ones are much the longest, 

 and usually a little crooked ; lengths to that of an upper arm-plate (8th 

 joint) 2.6, 2.8, 1.2, 1, .6, .3 : .8. Tentacle-scales none, or very minute and 

 rounded. Color dull indigo, lighter below, with arm-spines mottled with 

 yellowish. 



San Diego, California. Many specimens from shallow water, by Professor 

 Esmark. 0. magnifca is somewhat near, but has very thorny arm-spines. 



On the Species of Ophiothrix from the Waters of Western Europe and of 

 the Mediterranean. 



The genus Ophiothrix is usually the most perplexing in respect of 

 the identification of its species. Those of Europe make no exception, 

 as may be seen by the following list of names taken from the princi- 

 pal writers on echinoderms : — 



Stella seolopendroidps : Rosida scolopendroides, Linck de Stel. Mar., p. 52, 



PL XX VI., Fig. 42, 1733. 

 Asterias fragilis Abildgaard (O. F. Midler), Zool. Dan., p. 28, PL XCVUX, 



1789. 

 Asterias pentaphyllum : varia ; aculeata ; hastata ; fssa ; nigra Pennant, 



Brit. Zool, IV. 54, 55, 1812. 

 Ophiura fragilis Lamk., Hist, des An. sans VcrtcL., II. 546, 1S16. 



" tricolor " " " " « " 



Asterias tricolor Delle Ciiiaje, Memorie, III. 78, PL XXXIV., Fig. 9, 1823. 

 " ecldnata " " " " " 



" pentagona " " " " " 



" Cuvieri " " '• " 70. 



" Fcrussacii " " '• " " 



" quinquemaculata " " IV. 197. 



