ECHINODERMATA. 
627 
ECHINIDEA. 
Agassiz, A. List of the Echinoderms sent to different Insti- 
tutions in Exchange for other Specimens, with Annotations. 
Bulletin (No. 2) of the Museum of Comparative Zoology. 
Boston, 1863 (pp. 17-28). 
Fischer, P. Note sur les perforations de VEchinus lividus 
(Lamk.). Ann. d. Sci. Nat. V® ser. Zool. tom. i. 1864 
(pp. 321-332). 
Thomson, Wy. On the Embryology of the Echinodermata 
(VI. — The Embryogeny of the Echinidea). Nat. Hist. 
Rev. October, 1864 (pp. 581-611, with woodcuts). 
Wright {op. cit. pp. 21-34) gives a general account of the 
terminology of the hard parts in the Sea-urchins and their 
classification with reference thereto, reproducing, almost v'er^ 
batiniy the Introduction to his published Monograph of the 
Oolitic Echinidea. 
Wyville Thomson reviews the existing state of our know- 
ledge of the embryogeny of this order. His article, as might 
be supposed, is, in the main, a connected resum^ of the memoirs 
of J. Muller and Krohn on this subject, references, where 
heedful, being made to the writings of Busch, Derbes, and 
other observers. At present he would refer all pseudembryos 
with ciliated epaulettes and simple frame-rods to the genus 
Echinus j and those without epaulettes, with fenestrated rods, 
and with an azygous inferior process to the Spatangidce ] but, 
perhaps, such a generalization may be premature.^^ Of the 
embryogeny of the Cake-urchins nothing whatever is known, if 
we except Muller^s conjecture that a beautiful pseudembryo 
with a globular body, without ciliated epaulettes, with eight 
appendages, the styles of the four body-appendages fenestrated, 
and with an elegant reticulation of calcareous rods on the 
surface of the dome,^^ might belong to Echinocyamus. In con- 
clusion Thomson compares Pluteus with Bipinnaria, and oflfers 
some general comments on the exact relations of these and 
other pseudembryos to the young Ecliinoderms which they 
develop. 
Fischer seeks for a more exact expression of what we know 
of th'e boring-phenomena of Echinus lividus: His paper, after 
stating the problem, opens with a short description of the 
Biarritz coast, followed by an account of his observations on the 
perforations of E. lividus in the limestone rocks of that locality. 
Next he sums up the results of an examination of six series of 
rock-specimens containing similar perforations, preserved in the 
