followed by a more complicated one. The use of rudiment in this 

 sense is undesirable, because, in the interest of scientific accuracy, it 

 is important to restrict its meaning, as in German, to a structure 

 which is not destined to become more complicated, but which may have 

 been, either ontogenetically or phylogenetically, even more highly 

 developed than it now is. Origin and beginning are abstract terms, 

 whereas Anlage is more frequently used in the concrete ; basis and 

 foundation (Grundlage) convey a wrong impression that of the sub- 

 stratum upon which the structure is erected. The need of a new 

 word, which shall be used in the sense of Anlage, is evident. I 

 suggest the adoption of an already existing word, fundament, used 

 at present only in a sense with which the proposed usage will not 

 produce confusion. This word has been uniformly employed in the 

 present translation, and the reader will see how readily and naturally 

 it lends itself to this use. Fundament would thus bear the same 

 relation to foundation that Anlage does to Grundlage. 



I have also departed from authorised usage by sometimes employ- 

 ing for Bindegewebe and Stiitzgewebe the term sustentative (in a 

 mechanical sense) tissue, instead of connective tissue. My reason 

 for this is the narrower meaning of connective as compared with 

 sustentative. 



In deference to a custom still followed in Human Anatomy, the 

 author, in describing the relative positions of parts, has very generally 

 used anterior and posterior for dorsal and ventral, etc. Instead of 

 converting these expressions into terms which are independent of the 

 temporary position of the organism, as I should have preferred, it 

 has seemed better to indicate the direction by a bracketed word in 

 those cases where a misunderstanding was most likely to occur. It 

 has of course not been necessary to repeat this after each term of 

 direction, but only after the first one of a series, the reader's atten- 

 tion being thus sufficiently directed to the matter to prevent any 

 misconception. 



The rapid advances in Embryology make it impossible for a book 

 two years old to be a faithful reflection of the science of to-day in all 

 its branches ; there are some topics in which even radical changes 

 must be recognised. I have thought best, however, to reproduce the 

 book as it left the hands of its author, and to content myself with 

 calling the reader's attention to some of the topics in which the most 

 important advances have been made, such as the metamerism of the 

 head, and the plan and metamorphoses of the vessels of the visceral 

 arches. 



