490 



SCIENCE 



[N. S. Vol. XXXVII, No. 952 



passed by the higher Protremata in the later 

 faunas. This is as it should be, for they are 

 diverse expressions of the simplest brachiopod 

 structure. Broadly speaking, regardless of 

 their multitude, the species of the major di- 

 visions are all oboloid or linguloid in outline. 

 The disk of the oboloids has been oft re- 

 peated in the geological history of the brachio- 

 pods, though it has served to mask widely dis- 

 tinct genera ; but as for the sharpened Lingula- 

 form — it would seem there was a divinity that 

 shaped its end, for it has come down to this 

 day without much change, just enough in 

 fact to let us say that no true Lingula existed 

 in Paleozoic time, hard as it might be to prove 

 it. One can not restrain surprise at the 

 beauty of retention of much of this material, 

 the perfection of shell structure, of pallial 

 venation, ovarian and muscular impressions, 

 set forth on the plates by extremely effective 

 mechanical processes of illustration. The 

 quality of this illustration is most admirable, 

 and it would seem that the personal error of 

 portraiture has been here reduced to its low- 

 est terms. 



Should one, on cursory examination of this 

 host of newcomers in paleontology, wondering 

 over their relationships, their phylogeny and 

 precedence, venture to whisper to himself of 

 Orusia eurekensis or Otusia utahensis — who 

 was its father? who was its mother? had it a 

 sister? had it a brother? — these wisely sup- 

 pressed inquiries are answered on page 317, 

 which graphically sets forth the presumed de- 

 rivative relations of the genera discussed. 

 This page is exceedingly instructive. Beecher 

 found the brachiopod radicle best expressed in 

 the Cambrian genus Paterina, and his propo- 

 sition still holds pretty well under these later 

 studies. Walcott's radicle is hypothetic and 

 Precambrian, and its most direct expression 

 and outcome is his genus RusteJla which, 

 leaving no successors (in this table), stands 

 out in independence as the fortified proteg- 

 ulum adult. Nearest to this in close collateral 

 development stands Paterina, d, durable genus 

 reaching nearly through all Cambrian beds. 

 From a distinct collateral descend the obo- 

 loids and in a near-by line, but distinct as far 



as it has been tracked, the linguloids. These 

 three lines constitute the main stocks of the 

 Atremata. 



The Neotremata with definite cardinal sur- 

 faces (such genera as Acrotreta, Acrothele, 

 Trematoholus) indicate no marked converg- 

 ence toward the Atremata. Mr. Walcott 

 unites them, close to the Precambrian radicle. 

 This also he does with the Protremata (Bil- 

 lingsella, Syntrophia, etc.). Indeed, one of 

 the striking features of this table is its pal- 

 pable absence of evidence of Cambrian con- 

 vergence in the three great subclasses. 



In 1892-94, when Hall and Clarke's "In- 

 troduction to the Study of the Genera of 

 Paleozoic Brachiopoda " and " Introduction 

 to the Study of the Brachiopoda " appeared, 

 there were 28 recognized Cambrian genera. 

 Dr. Walcott presents a total of 49 genera and 

 subgenera of Atremata and Neotremata from 

 the Cambrian. But it is to be noted that, not- 

 withstanding its title, the work is not ex- 

 clusively given over to the Cambrian faunas. 

 The author has included a number of related 

 genera and species, of all three subclasses, 

 from the Ordovician, which help to make 

 clearer the relations and range of these primi- 

 tive expressions. 



The scientific public knows that even with 

 this vast contribution to our knowledge of the 

 Cambrian fauna. Dr. Walcott's work is very 

 far from complete. We have been let far 

 enough into his accumulated Cambrian treas- 

 ures to realize that his brachiopod book is but 

 a foretaste, an intimation of the whole fauna 

 under his eye. We can not restrain amaze- 

 ment at the tremendous expansion of ideas 

 regarding the profusion and diversity of the 

 Cambrian fauna which has followed the work 

 of his hands. It is his own fault if we are 

 led daily to expect the unexpected from this 

 rich depository of life. In beauty and excel- 

 lence of preservation the Cambrian beds of 

 the Canadian Rockies, which he has especially 

 upturned, surpass nearly all deposits of a 

 later date, and with the light that they have 

 cast upon familiar organisms long known to 

 us from later beds, we have now to rehabili- 

 tate many familiar conceptions. In ultimate 



