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REPORT ON ZOOLOGY, MDCCCXLII : 
anus, is divided into two sub-divisions, Ophiurce and Euryalce. The 
Ophiurce have arms fitted only for walking ; their skin is either naked, 
or covered with hard scaly granules, spines, and plates ; on the abdominal 
side of the disc are found five interbrachial shields between the roots of 
the arms, in which a larger one is distinguished as the shield of the 
mouth ; a wedge-shaped ossicle projects towards the mouth from each 
interbrachial shield as a maxilla, from which a tooth-process is also 
directed towards it. The margins of the five-cleft mouth are either naked 
or covered with papillsB, which appear either simple or serrated on their 
margins. The tooth-process bears teeth in all Ophiurce, and in some also 
papillae. On the arms two rows of ventral and dorsal, and two of lateral 
plates, can be distinguished. On the abdominal aspect of the arms, on 
each side of a ventral shield, there is an opening for the passage of a 
filiform tentacle. Muller and Troschel divide these Ophiurce into two 
families, of which the first contains such animals as have four genital 
clefts in each interbrachial space, and papillae on the cleft of the mouth. 
To this belong the two genera, Ophioderma and Ophiocnemis; the 
former with three species, of which 0. cinereum and Wahlhergii are new ; 
and the latter with one species. The second family embraces those 
Ophiurce, which have only two genital-plates in each interbrachial space. 
The first group of this family are the Ophiurce, which have the mouth- 
cleft covered with papillae. The genera which are clothed on the disc and 
arms with hard parts are first, — Ophiolepis, with seventeen species, of 
which the new are, 0. cincta, Sundevalli, imbricata, M. and T. : Ophio- 
coma, with eighteen species, of which 0. erinaceus, Wendtii, Schoen- 
leinii, dentata, pica, picta, arctica, M. and T., serpentaria, Val., 
lineolata, Desjard., are new; Ophiorachna, with four species, of which 
O. infernalis, gorgonia, and septemspinosa, have not hitherto been de- 
scribed ; Ophiacantha, with two species, of which O. spinulosa is new : 
and Ophiomastix, with one species. Next follow the two genera Ophio- 
myxa and Ophioscolex, in which the disc and arms are naked. Each 
genus contains a single species. In the second group are placed the 
Ophiurce with no papillae on the clefts of mouth. It comprehends the 
two genera, Ophiothrix and Ophionyx, of which the former has eighteen, 
and the latter four species. The characters of the genera of the Ophiurce 
are also taken from the spines, granules, scales, and plates of the cover- 
ing of the body, according to their presence, construction, and arrange- 
ment ; and, at the same time, the circumference of the mouth, which is 
covered with spine or tooth-like papillae, and with simple or crowded 
papillae, atfords additional distinctions. 
In the Euryalce, the second sub-division of the Ophiuridce, the arms 
are grasping organs, and can be rolled up towards the mouth. They 
have no lateral spines, like the Ophiurce, but two rows of small papil- 
lary crests on the abdominal side of the arms. Muller and Troschel 
first characterize a new genus, from a species hitherto undescribed, the 
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