REVIEWS — PRINCIPLES OF ORGANIC ARCHITECTURE. 285 



trutli. "Witli regard to the Protozoa, Dr. Ogilvie offers little 

 information, and what lie does give relates almost exclusively 

 to Ehizopoda. In considering this lowest sub-kingdom, we have, 

 on the one hand, to guard against mistaking for distinct forms 

 embryonic conditions of other minute animals, and on the other to 

 decide whether certain tribes belong to the animal or vegetable king- 

 dom. Mistakes have been made by eminent naturalists in both these 

 directions, but we arrive at the conclusion that after setting aside 

 those tribes which are truly vegetable, and making every allowance for 

 larval forms, there remain three classes of Protozoa, Infusoria having 

 something of a fixed shape, an oral orifice, and some approach to a 

 special external covering. Mliizopoda destitute of these characters, 

 deriving nutriment by involving the prey in the sarcode, and getting 

 rid of hard or useless portions by openings in this primitive gelati- 

 nous substance which can at the will of the animal be varied in form, 

 or extended into ai-ms or feet. The Ehizopods are either naked or 

 enclosed in a horny, silicious, or calcareous case which may be simple 

 or composite from the production of germs having a definite arrange- 

 ment. Porifera resemble E-hizopoda in their substance, but are dis- 

 tinguished by growing in masses formed about channels through 

 which the water which yields the required nutriment, probably de- 

 caying animal and vegetable matter, is made to pass by a ciliary 

 movement, and which are kept open by means of hard parts, horny, 

 silicious, or calcareous, in the form of spicula or of a net-work of 

 fibres. In the present state of knowledge these characters seem to 

 us clear and suflB.cient as distinctions of classes, and well fitted to 

 assist inquirers in gaining a general view of the system of nature. 

 Dr. Ogilvie' s 8th chapter, entitled, " the law of typical form and 

 manifestation of design, co-extensive with organic nature," is an ex- 

 cellent statement, in a concise yet intelligible manner, of a most im.- 

 portant principle. We quote a short parapraph from his concluding 

 remarks : " It is unnecessary farther to multiply instances in illustra- 

 tion of the law of typical form, as those now adduced appear sufficient 

 to show there is some principle involved in the construction of 

 animals beyond the mere adaptation of their organization to their 

 appropriate spheres of life. Tet we shall certainly never disparage 

 the indications of the latter, if we pursue the study of nature with 

 unprejudiced minds ; for even in the common type, and still more 

 obviously in its modifications, characteristic of classes and minor 



VOL. IV. V 



