Vol. XLIII. July, IQ22. No. I. 



BIOLOGICAL BULLETIN 



NORMAL VERSUS SUBNORMAL DEVELOPMENT IN 

 PATIRIA MINIATA. A CAUTION TO LABO- 

 RATORY EMBRYOLOGISTS. 



H. H. NEWMAN. 



(From the Hopkins Marine Station of Leland Stanford University and the 

 Hull Zoological Laboratory of the University of Chicago.) 



(TWENTY-SIX FIGURES.) 



Years of experience in rearing marine organisms in finger-bowls 

 of sea water have made the present writer somewhat skeptical as 

 to the validity of life histories worked out under these conditions. 

 The average morphologist who is unfamiliar with the modern re- 

 finements of experimental physiology or of ecology scarcely real- 

 izes how abnormal as the environment of a marine organism is a 

 bowl of stale and stagnant sea water kept at room temperature and 

 in reach of direct sunlight. Such an organism is adjusted in all 

 of its physiology to the open sea with its uniform temperature, its 

 delicately balanced oxygen content and hydrogen-ion concentration, 

 and its opportunities for selecting light and shade of optimum 

 intensities. 



In view of these discrepancies between the natural and the arti- 

 ficial environment it would seem remarkable that finger-bowl cul- 

 tures ever could approximate normal development. Some organ- 

 isms, however, are hardy and tolerant of suboptimal conditions and 

 develop in finger-bowls with only slight departures from the nor- 

 mal. Very many marine organisms are, on the other hand, ex- 

 tremely sensitive to suboptimal environmental conditions and show 

 the effects of the finger-bowl environment all too plainly. 



A conspicuous example of an organism highly sensitive to sub- 

 optimal environmental conditions is the egg of the California star- 

 fish, Patiria miniata, with which the writer (Newman, '21 a, '21 b) 

 has dealt at some length, calling attention to the numerous anom- 



