190 
CRUSTACEA. 
Richiardi, S. Bomolochus ostracionis. Arch. p. Zool. ii. 
pp. 47-69j pi. 1. 
Sars^ Mich. Bidrag til Kundskab om Christianiafjordens 
Fauna. II. Crustacea. Christiania : 1870^ 8vo, 48 pp. 3 pis. 
Smith, Sidney F. Notes on American Crustacea. No. I. 
Ocypodoidea. Tr. Conn. Ac. ii. 1870, 84 pp. 8vo, 4 pis. 
Streets, T. Hale. Notes of some Crustacea of the genus 
Libiniaj with descriptions of four new species. P. Ac. 
Philad. 1870, No. 3, pp. 104-107. 
Verrill, a. E. Observations on Phyllopod Crustacea of the 
family Branchipidoi, P. Am. Ass. 1869 [published July 
1870] . 18 pp. 
Wagner, Nicol. [Hyalosoma dux^ a new form of Amphipod 
Crustacea. Transactions of the first meeting of Russian 
naturalists at St. Petersburg, 1868, pp. 218-238, 4 pis.] 
Wright, Edw. Perceval. On a new species of the genus 
Pejinella. Ann. N. II. (4), vol. v. p. 43, pi. 1. 
Morphology. 
A. Dohrn publishes two papers concerning the common 
points in the embryonic development and the probable common 
origin of the different orders of the Crustacea. In the first he 
points out not only that the Decapoda pass during their deve- 
lopment from the stage of Nauplius to that of Zoea (the sup- 
pression of these stages, as in Astacus fluviatiliSy being an ex- 
ception), but also that in the other orders of Crustaceans 
there are traces which suggest the conclusion that they have 
had in former times such a Zoea-stage ; he regards the dorsal 
spine as a very essential character of Zoea, and thinks that the 
dorsal accumulations of cells in the embryos of some Isopods 
and Amphipods, the so-called micropyle-apparatus in the Am- 
phipods, the dorsal sucker of the larvie of Limnadia and the 
Cladoccra, the frontal fixing apparatus of Caligus and Chalimus, 
and the peduncle of the Cirripeds are to be regarded as trans- 
formations of the dorsal spine of Zoea ; several other hitherto 
enigmatical organs in the larvae of various Crustacea are inter- 
preted in the same way. Jen, Z. Nat. v. pp. 471-491. 
Tn the second, very extended, paper he endeavours to trace the 
probable origin of all groups of the Crustacea from a Nauplius, 
which itself may have taken* its origin from lowly organized 
members of the class Vermes. Archizoea is regarded as an 
intermediate stage between Nauplius and Zoea. The metamor- 
