REPORT ON THE OPHIUROIDEA. 



85 



Table of Species of Ophiornusium — continued. 



Disk covered by large radial shields, and small irregular scales, among which the 

 primary plates are scarcely conspicuous, ..... 



\Oph. 



iomusium planum. 



Several flat angular plates in lower interbrachial space besides the large one ) 



joining the mouth shield. Genital scales wide. No under arm plates > Ophiornusium lymani. 

 beyond the second or third, . . . . . I 



Upper disk covered by large swollen radial shields, with minute imbricated ) 



scaling in centre. Arms wide and thick, with side arm plates much swollen > Ophiornusium laqueatum. 

 and rounded. Upper arm plates broad diamond-shape, . . . j 



Disk covered by large angular swollen plates, 1 Upper disk plates bearing large ) „ , . 



of which the interbrachial marginal is largest. tubercles, . . . / Ophiornusium acuferum. 



Arms wide and thick, with side arm plates \ 



much swollen and rounded, and bearing a | 



spine on their upper surface, . . J Upper disk plates smooth, . Ophiornusium liitkeni. 



Most of the lower interbrachial 

 space outside the mouth 

 shield is occupied by broad 

 genital scales and a great ■ 

 central plate. No under 

 arm plates beyond the 

 third. 



Ophiornusium validum. 



Four small, equally spaced arm spines. Small 

 upper arm plates. The great lower inter- 

 brachial plate has usually two, much smaller at 

 its outer corners, .... 



Two minute arm spines set low down. Resides ) 



the great interbrachial plate below, there are > Ophiornusium simplex. 

 three others along the margin, . . j 



Two minute arm spines set back from edge of 

 plate. Only one lower interbrachial plate, 



Three short, stout, well-defined arm spines. Disk " 

 plates thick, separated by narrow grooves, and 

 arranged above like steps. Side arm plates 

 flaring a little outward, 



Two or three minute arm spines. Disk plates 

 coarse, swollen, and irregular. Two or three 

 marginal plates besides the central one in the 

 lower interbrachial space, 



Five short, sharp, well-marked arm spines. The 

 great lower interbrachial plate is separated by 

 a square one from the mouth shield. Margin 

 of disk set with small points, 



> Ophii 



iomusium lunare. 



Ophiomusiam scalare. 



■ Ophiornusium testudo. 



Ophiornusium granosum. 



Basal side arm plates very flat and wide, en- 

 croaching much on the interbrachial space, 

 and bearing stout spines on their outer 

 edge. First under arm plate similar to 

 those beyond, and furnished with a ten- 

 tacle scale, .... 



Genital scales meeting on median 1 ^ hiomusium pu l c hellum. 

 line of lower interbrachial space. J r 



First side arm plates meeting in \ 



medianlineof lower interbrachial > Ophiornusium flabellum. 

 space, . . . . ) 



Ophiornusium serratum, Lym. (PI. II. figs. 1-3 ; PI. XXXIX. fig. 10). 



Ophiornusium serratum, Lym., Bull. Mus. Comp. Zool., vol. v., part 7, p. 109, pL i. figs. 23-25 ; 

 also part 9, p. 220, 1878. 



Arms rather slender and tapering, cylindrical or but slightly wavy. Upper and 



