6 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



without building a floor as it proceeds. It differs from the embry- 

 onic young only in the length of this second chamber and its various 

 modifications of ornamentation and relative proportions which con- 

 stitute the specific characters in the various species of Comuspira. 



Occasional specimens show a reduction in the size of the tube in 

 the last formed portion as in senescence in some Mollusca. In 



Fig 4. Cobnuspiba foliacea ( Philippi). X24. Complete specimen, the young o? which is shown 



in pio. 5. Specimen shows tub later "partitions" developed in the larger, outer coos of thh 

 test. The last posmed chamber was partially broken when found. Viewed by transmitted 



LIOHT. 



others there is a tendency which may be considered rather more 

 prophetic in its nature. In the specimen figured here in outline 

 (fig. 4) is shown a recent specimen which upon first examination 

 seemed to have no characters unlike typical specimens and it was 

 selected for mounting in balsam for a study of the early coils. After 

 mounting examination showed a partial division into chambers 



