342 Scientific Intelligence. 



and to attempt to explain the degree of their usefulness is unsci- 

 entific. 



The problems in the development of life are : (l) Disappear- 

 ance of extensive groups of plants and animals ; (2) sudden and 

 extensive development of new groups ; (3) absence of connecting 

 forms between great groups of plants and animals, and (4) lack 

 of understanding of the entire development of life. The first 

 problem seemingly has its explanation in the inter-changing of 

 sea and land and the resulting climatic variations ; paleontologic 

 biota, on the other hand, are but fragments of former progressive 

 and repressive assemblages. 2. Imperfection of the local and 

 regional paleontologic records is more apparent than real ; present 

 known record not only a fragmentary but very much scattered 

 one ; new invading biota indicate lost records, elsewhere recover- 

 able, therefore no actual sudden appearance of new groups. 3. 

 Phylogenetic material as yet insufficient and too greatly scattered 

 in museums ; of small groups there is much connecting material 

 but none between classes, orders, etc. 4. Present methods of 

 explanation not scientific and according to nature but philosophic. 



Stein mann's phylogenetic-historic methods are peculiarly his 

 own. He complains (wrongfully) about systematists basing their 

 classification on single characters, thereby displacing the true 

 relationships of forms. He would take the entire organism into 

 consideration and group them historically. We will test his 

 results along a single line, namely the Brachiopoda. The family 

 Orthidae is said to be extinct since the Permian, but Steinmann 

 would have us believe that descendants of this stock in Dahna- 

 nella still live in Megerlea and Kraussina. His progressive 

 series are the orthid Dalmanella, the rhynchonellid Rhynchonel- 

 lina, the terebratuiids Megerlea and Kraussina, because all are 

 said to have the same general external expression (homomorphic) 

 while the arm supports are progressive from crura to loops. 

 Testing this sequence in the light of chronology, we see that Dal- 

 manella disappears with the Devonian while Rhynchonella does 

 not appear until, and is restricted to, the Jurassic, and the other 

 genera do not appear until the Tertiary. No attention is paid to 

 the fact that Rhynchonelllna is impunctate, while the punctate 

 shell structure of Megerlea and Kraussina is very different from 

 Dalmanella. Then too no orthid has deltidial plates while the 

 development of the loop both ontogenetically and chronogeneti- 

 cally in Megerlea and Kraussina indicates beyond a doubt that 

 these genera never arose in Rhynchonellina and not at all in 

 Dalmanella. 



The cemented bivalves Rudistidae are said to have the same 

 general organization as the ascidians and the slight differences 

 that exist are thought to be due to reduction in the latter, caused 

 by prolonged (geological) sessility. Since Cretaceous times the 

 Rudistid descendants have lost their shells and are now the 

 ascidians. On the other hand, Salpa are shell-less brachiopods 



