BIBLIOGRAPHY. 221 



Structural and Systematic Conchology : an intro- 

 duction to the study of the mollusca, by Geo. W. Tryon, Jun., 

 Conservator of the Conchological Section of the Academy of 

 Natural Sciences of Philadelphia. 



This large and important work is based upon the excellent 

 Manual of S. P. Woodward, and is uniform with, and intended 

 as an introduction to the author's larger work, the " Manual of 

 Conchology," now in process of publication. 



Mr. Tryon who is well known for his great knowledge of 

 systematic conchology, shows his skill in the treatment and 

 arrangement of the different groups treated of 



The broad facts of the science, the knowledge of which 

 are necessary for the young student, are given with commend- 

 able clearness and conciseness. 



The author commences his work by giving the classifica- 

 tion of the entire animal kingdom, especially dwelling upon the 

 peculiarities of second group — Malacozoa. This is divided 

 broadly into the Acephala and Encephala (the latter group is 

 divided into four classes — the Cephalopoda or cuttle fishes, 

 the Pteropoda of which the genus Clio is an example, the 

 Gastropoda or snails, and the Scaphopoda or Solenoconcha 

 the Dentalia or tooth shells. The Molluscoidea are divided 

 into Brachiopoda, Tunicata, and Bryozoa. Under the head 

 ' Anatomy,' the external features, the skin, the shell, the oper- 

 culum, the cartilages, the organs of motion, the nervous system, 

 &c. are treated in a very full and elaborate manner, conveying 

 not only the general characteristic peculiarities under each 

 head, but many of the special ones peculiar to particular species. 



The habits and economy are next considered. Under 

 this heading the parasites, enemies, the mimicry, &c., are 

 detailed. 



The geographical distribution is fully given ; the provinces 

 are practically adopted from Woodward, and a similar map, 

 but of larger size, still further shows the range of the different 

 genera. 



