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REPORT ON ZOOLOGY, MDCCCXLII : 
The Asteriadw have, last year especially, found many zoological 
labourers. Besides the already mentioned contributions of Forbes and 
Grube, various others remain to be mentioned, viz., — Forbes on the Aste- 
riadce of the Irish Sea, in Memoirs of the Wernerian Society, 1839, t. viii. 
1, p. Ill ; Agassiz Notice sur quelques points de FOrganization des 
Euryales, accompagnee de la description detailee de I’espece de la Medi- 
teranee ; Memoires de la Societe des Sciences Naturelles de Neuchatel, 
1839, vol. ii. ; Thompson, Ann. Nat. Hist. vol. v. 1840 ; and Gray, ibid, 
vol. vi. 1840. The reporter, however, refrains from analyzing these, 
as in the admirable work on the Asteriadw, lately published by Muller 
and Troschel, the appearance of which must have been most anxiously 
expected from the cursory remarks (Archiv. 1840) already published by 
these Naturalists for two years past, all the matter belonging to this 
class has been as completely elaborated as can be desired (System der 
Asteriden. 1842). The descriptions of the Asteriadw are so excellently 
given in this work, and the genera and the species so accurately defined, 
that it has afibrded the reporter a real pleasure to arrange, with this 
book in his hand, the collection of Asteriadw belonging to the zoological 
cabinet at Erlangen. The plates, which represent only individual 
portions of these Echinodermata, are distinct, and serve to show, where 
description is insufficient, the highly complicated arrangement of the 
different parts of the cuticular covering, viz., — the spines, plates, 
granules, tubercles, pedicellaria, &c. These plates accomplish their aim 
completely by their extraordinary exactness, which is a great advantage, 
as one often takes up such monographs, richly furnished with illustra- 
tions, in order to define, by their means, zoological objects, and yet, by 
the diffuse descriptions, and dazzlingly coloured plates, can only make 
out few species with certainty. 
Muller and Troschel have prefixed an introduction to the systematic 
descriptive part of the monograph of the Asteriadw, in which their orders 
are characterized. They are defined, generally, as those Echinodermata 
which have a star- shaped or polygonal, mostly pentagonal form, and, 
besides the cuticular skeleton, have also an internal one. They are divided 
into two divisions, Asteriadw and Ophiuridw; the former have furrows on 
the abdominal side, and a corporeal cavity stretching from the disc to the 
arms or processes, which contains the viscera. In the Ophiuridw, with 
their two sub-divisions, Ophiurw and Euryalw, the abdominal furrows 
are wanting, and the viscera are confined to the cavity of the disc. In 
the family of the Asteriadw, there is frequently an anus on the dorsal 
side of the disc, in several genera central, but mostly sub-central. In 
this introduction, a view of the different divisions has been given, as 
they have hitherto been characterized by authors. In the general de- 
scription of the first family of Asteriadw, both Naturalists have drawn 
attention to the pedicellarias, which, as small nipper-like two to three- 
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