THE FORAM2NIFERA 



The walls are chitinous tubes with a calcareous deposit. They 

 are imperfectly divided into chambers, and are not perforated. A 

 flagellate stage did not come under observation. The protoplasm 

 contains large numbers of small nuclei. 



ORDER Textularidea. 



This order contains a number of genera which are excellent 

 examples of the multiform (biformed and triformed) condition of 

 the test. 



The arrangement which has been regarded as typical of the genus 

 Textularia is one with two rows of alternating chambers, but Schubert 

 has recently drawn attention to the fact (65) that many, if not 

 all the forms included in it, are biformed, some having the earlier 



Fio. 43. 



Spiroplecta (Textidaria) sagittula, Def. A, the megalospheric, B, the microspheric form, 

 X 55 ; b, the earlier chambers of the latter, x 150. A and B represent specimens stained, and 

 mounted in Canada Balsam, and show the nuclei. 



chambers arranged in a planospiral, others in a rotaloid, and others 

 again in a triserial manner, before the characteristic biserial arrange- 

 ment is assumed. Thus "Textularia" sagittula, Def., begins as Schubert 

 states, and as I have also had occasion to observe, in a planospiral 

 series of chambers, the arrangement being, in fact, that character- 

 istic of the genus Spiroplecta. Out of a batch of 63 specimens of 

 this species collected at Plymouth in the month of July, I found 57 

 to be megalospheric, and 6 microspheric, a proportion of 9 to 1. 



8 



