REPORT ON THE OPHIUROIDEA. 



123 



scale. The three arm bones nearest the disk margin have their tops elongated outward. 

 The tops of the mouth frames though small are considerably furrowed and grooved, but 

 are destitute of a peristomial plate, or have only a thin lime crust. A short small jaw, 

 universally characteristic of the genus, supports the intimately connected jaw plate and 

 the large, flat, oblong teeth. All the species have a genital- plate of the general shape 

 just described ; and the genital scale also is similar, yet varies considerably in length, 

 sometimes being only two-thirds as long as the plate {Amphiura concolor) ; but again 

 being continued, by slender additional pieces, quite to the mouth shield {Amphiura 

 angularis). As a rule the peristomial plate is wanting, or feebly developed ; never- 

 theless, in {Amphiura concolor) it is of good size, pretty thick, and divided in two 

 pieces. (See PI. XL. figs. 16-18.) 



Table of Species of Amphiura. 



Only two mouth papilla3 on either side, whereof one is at the apex of the 



mouth angle. 



o 



'T3 



i^g 





M-^ 



to 

 a 



i 



Eidit stout, sharp arm spines. Basal mouth papillaj siiini- j ^ , . 

 5 '11 r 1 1 V. Amphiura crassipes. 



Ten stout, sharp arm spines. Basal mouth papilla wide and | 



scale-like. Tentacle scales very large, one overlapising > Amphiura maxima. 

 the other, . . . . . . j 



Seven fiat, blunt arm spines, with rough ends. Disk scales ) 



small, but rather thick. Tentacle scales small. Upper J- Amphiura verticillata. 



arm plates rounded, . . . . . j 



kSix stout, blunt arm spines, with a small beak at their ends. 



Disk scales delicate. Upper arm plates rounded. Ten- ^ Amphiura divaricata. 



tacle scales conspicuous, .... 



' Three or four tapering arm sjjines ; the lowest but one bent, and 

 the lowest longest, ...... 



Four straight, tapering arm spines. Disk scales delicate. Upper 

 arm plates thin, . . . 



Six short arm spines, the lowest stoutest. Disk thin and flat. 

 Disk scales extremely thin, . . ... 



O ITS 



o 



\ Amphiura complanata. 



> Amphiura hellis. 



> Amphiura Candida. 



o 





:3-3. 



a 



Kve to eight tapering, straight arm spines. Outer mouth 

 papilla scale-like. A notch in outer side of under 

 arm plates, ...... 



Six stout, tapering, straight arm spines ; the lowest longest, 

 and one curved. Outer mouth papilla spiniform, 



Four or five stout, short, arm spines. A rudimentary 

 mouth jiapiUa at outer corner of mouth slit. Disk ,- 

 scaling even and well marked, . . . . ) 



Four or five stout, sliort, arm spines. Primary plates con- 

 spicuous among the disk scaling. 



Five arm spines, short, stout, and beaked ; disk scaling very 

 fine ; and below, difficult to be seen. 



Seven or eight short, blunt, crowded, thick arm spines. 

 Outer mouth papUla scale-like, 



Similar to preceding, but lower scaling coarser ; under arm (^ 

 plates wider, and arm spines thicker, . . . / 



Ampihmra chiaji.i. 



> Ampihiura otteri. 



> Amp)hiura eugenim. 



AmpMiira studeri. 

 > Amphiura palmeri. 

 \ Amp)hiura mcdiierranea. 



AmpMura incana. 



