OP CONCHOLOGY. 361 



We cannot pause to do justice to all parts of this paper, 

 and reluctantly omit the author's remarks on the polarity of 

 the Mollusca, and comparison in this respect, and the relations 

 of its classes, with those of the other sub-kingdoms of animal 

 life. 



The following definition is given of the Saccata, with a sy- 

 nopsis of the classes : — 



"SACCATA. 



(1) Animals of a varied form, without a radiate structure and 

 without articulations. 



(2) Stomach and viscera enclosed by a fleshy sac, which may 

 he closed or open, at either one or both ends. 



(3) Princijml nerve masses, consisting of ganglia, which are 

 adjacent to, or surround the sesophagus. 



(4) Intestine bending inivard, or having an outward flexure. 



(5) Heart on the outer bend of intestine. 



r Sac open at ( Cephalopoda. 

 ' HoLozoic, OR I anterior end. ( Gasteropoda. 



Saccata. 



TYPIC. ■< 



Month opens j Sac opens at 

 anteriorly. v both ends. 



Lamellibranchiata. 



Phytozoic, f Sac open at ( Tunicata 



OR HEMiTYPic. 1 posterior end. | 

 Mouth opens -\ 



I posteriorly. Sar Hosed ( Brachiopoda. 



I. bac Closed. | Polyzoa." 



Geological Survey of California. Palaeontology. Vol. I. 



Carboniferous and Jurassic Fossils: BY F. B. MEEK. 



Triassic and Cretaceous Fossils: BY W. M. GABB. 



(Published by authority of the Legislature of California. 

 4to, pp. XX., and 243, with 32 plates. 1864.) 



This volume is alike creditable to the State which has au- 

 thorized its publication, and to the authors, artists and print- 

 ers engaged in its production. It is the most beautiful speci- 

 men of typography and engraving that we have ever seen in 

 an American scientific work. The plates, executed from 

 drawings by the respective authors, are truly magnificent. 



The following are the contents (conchological) of the vol- 

 ume: — 



Preface: BY J. D. WHITNEY, State Geologist. 

 Description of the Carboniferous Fossils: BY F. B. MEEK. 



Seven species are described, three of them new. 



