McClung.] Microscopic Organisms of Upper Cretaceous. 425 



pie, homogeneous band, but in some specimens it is perforated 

 by from fifteen to twenty oval apertures placed radially, or is 

 crossed by numerous radial stride. The substance of the rim 

 and the cross-bars appears to be continuous. 



Just as remarkable and less well defined than the Coccoliths 

 are the Rhabdoliths. In form these vary considerably, the most 

 common types being a small cross, with arms of variable length, 

 and a flat, funnel-like form. In the specimens examined, the 

 latter was the more common, and was plainly visible in all the 

 details. The narrow part representing the neck of the funnel 

 was always broken, and there is no way of knowing how long 

 it may originally have been. On the whole, the appearance is 

 very suggestive of spinous fragments from some comparatively 

 large organism. 



With regard to the true character of the Coccoliths and Rhab- 

 doliths, little definite knowledge exists. The former were 

 named in 1858, by Huxley, and the latter by Dr. 0. Schmidt, 

 in 1872. Huxley considered that the Coccoliths were formed 

 by the agency of a protoplasmic substance of indefinite size and 

 uncertain composition, named by him Bathybius. This gelati- 

 nous substance was supposed to be found at great depths in the 

 ocean, and was observed to inclose numerous Coccoliths within 

 its confines. Since, however, the Bathybius has been produced 

 artificially by the deposition of sulphates from solutions on the 

 addition of alcohol, this origin of the Coccoliths had to be dis- 

 pensed with. Therefore, at the present time it may be said the 

 question of origin stands about where it did at the time the 

 forms were discovered. A similar statement may be made con- 

 cerning the Rhabdoliths. 



But four species of Foraminifera were discovered in all the 

 rocks of the Upper Cretaceous. These were subject to no little 

 variation, such as might have been made the basis for the 

 establishment of other species or varieties, but in the opinion of 

 the writer these are merely modifications due to the conditions 

 of growth. This view receives the support of A. Goes, who, in 

 his work, " The Reticularian Rhizopods of the Caribbean Sea," 

 inveighs very strongly against the practice of naming species 



