abstracts: zoology 609 



meris, subsp. nov., southern Mexico; C. a. texensis, central and northern 

 Mexico and southwestern United States; and C. a. inferior, subsp. 

 nov., Lower CaUfornia. The South American Chordeiles rupestris has 

 three forms: C. r. rupestris, from middle and northern Brazil and eastern 

 Bolivia; C. r. xyostidus, subsp. nov., central Colombia; and C. r. zaleucus, 

 subsp. nov., eastern and central Peru. .H. C. O, 



ZOOLOGY. — Une etude philosophique de la relation enire les crinaides 

 actuels et la temperature de leur habitat. Austin H. Clark. Bulle- 

 tin de ITnstitut Oceanographique, Monaco, No. 294. 1914. 



Of the two suborders of recent unstalked crinoids (comatulids) one, 

 Macrophreata, is chiefly developed in the colder waters while the other, 

 Oligophreata, occurs chiefly in the warmer seas. 



In the Macrophreata the maximum number of families is found 

 between the temperatures of 50° and 66° Fahrenheit, from which point 

 the number gradually decreases as the temperature becomes less, and 

 abruptly decreases as the temperature increases; in the Oligophreata 

 the maximum number of families is found between 60° and 65° Fahren- 

 heit, from which point the number gradually decreases as the tempera- 

 ture increases, and abruptly decreases as the temperature becomes less. 



Considering all the comatulid families together, the greatest repre- 

 sentation is between 55° and 65°, with the emphasis as 60°-65°; the 

 few families of stalked crinoids of which we have adequate knowledge 

 also occur at these temperatures. 



Thus it would appear that the temperature range between 55° and 

 65° Fahrenheit (12?78 and 18?33 Centigrade) represents the optimum 

 temperature for the recent crinoids as a whole. 



The species occurring between these temperatures represent very 

 conservative types, all of the more aberrant types being developed in 

 warmer or colder water. Furthermore, it is within these temperatures 

 that the fossil crinoids find their closest living representatives. Hence 

 it is suggested that it was possibly within these temperatures, between 

 55° and 65° Fahrenheit (12?78 and 18?33 Centigrade) that the post- 

 pala?ozoic crinoid fauna was chiefly developed. A. H. C. 



