der niederen Thiere während der J. 1868—1869. 261 



Ophiomitra Lym. Teeth: numerous, sraall, nearly equal 

 mouth-papillae; no tootli-papillae. Disk flat, circular, and erect, cove- 

 red with scales and radial shields, and beset with thorny spines or 

 stumps. Arm-spines rongh. Side arm-plates large and nearly or 

 quite meeting above and below. 



Ophiochondrus Lym. Teeth and naouth-papillae: no tooth- 

 papillae. Disk granulated; contracted, so that the interbrachial 

 Spaces are re-enteriiigly curved and are fiirther much reduced by 

 the encroachement of the stout arnis. Side mouth-shields wide and 

 thick and meeting within. Side arm-plates meeting below, and there 

 closely soldered so as to forme a continuous beit. Two genital slits 

 in each interbrachial space. 



Ophiotliamnus Lym. Teeth: no tooth-papillae : mouth-pa- 

 pillae, of which the outer is much the broadest. Side mouth-shields 

 long and stout, extending outside the mouth-shields and making, 

 with them, a compicuous raised pentagon. Side arm-plates large, 

 meeting above and below, and bearing slender, rough spines on their 

 sides. Disk pufifed and overlying the bases of the arms, covered 

 with scales and radial shields, which are beset with spines. 



Ophiomy ces hym. Theet; no tooth-papillae; numerous wide, 

 flat mouth-papillae , which are turned downwards and outwards, and 

 arranged in two or more imbricated rows, covering the whole 

 mouth-angle. Side mouth-shields large and meeting above. Disk 

 finely scaled, without visible radial shields. Arm-spines withiu the 

 disk shorter, stout er, and of a different character from those of 

 the joints further out. 



Ophiocreasljjm. (e fam. Asterophytid.) Disk and arms uni- 

 formly covered by soft skin bearing microscopic grains. Disk small; 

 its interbrachial outlines re-enteringly curved ; five pairs of narrow, 

 rather high radial ribs running from the margin quite to the centre. 

 Arms simple, very long and smooth; the joints indicated by very 

 slight depressions. Small arm-spines standing just above the tenta- 

 cles. Teeth: one or more tooth-papillae; mouth-papillae arranged 

 in a clump on the side of the mouth-frame, and above its lower 

 edge. Two genital slits, nearly as long as the disk is high. (Un- 

 terscheidet sich von x^steroschema besonders durch den Besitz der 

 Zähne.) 



Ästrogomphus Lym. Disk wäth ten low, very narrow ra- 

 dial ribs, running nearly to its centre and beset with numerous spines. 

 Arms simple. Skin of arms and disk covererd by a mosaic of small 

 flat grains; the joints of the former distinguished by ridges, each 

 of which consists of belts of grauules, some of them bearing minute 

 hooks. Arm-spines like thorny stumps and arranged in clumps just 

 above the tentacle pores. Teeth: tooth-papillae and mouth-papillae 



