Dr. 0. Schmidt on Coccoliths and Rhahdoliths. 369 



fig. 15), which is so remarkably abundant among living cocco- 

 liths, I can hardly detect in the deposits at Brindisi ; but it 

 came most prominently into consideration with regard to 

 reproduction. The objection is therefore not serious. 



My supposition, however, as to the independence and repro- 

 duction of the coccoliths, is established by the discovery of a 

 second corpuscle accompanying BatJiT/bms, which is much 

 simpler and clearer, and consequently easier to check in its 

 individuality. It also presents certain points of comparison 

 with the coccoliths. We call it RhahdoJithes (PI. XVIL figs. 

 20-35). Its first foundation is a little rod, which may be traced 

 of all sizes from O'OOl to 0"005 millim. The developed forms 

 range between 0*0054 and 0*004 millim. in length. Together 

 with the cylindrical rods there occur about an equal number 

 which are thicker at one end than at the other (fig. 22). They 

 then acquire a button-like or globular terminal inflation (figs. 

 21, 23) ; and around this is produced a circlet of globules (fig. 

 24 &c.) which rarely exceed six in number. 



The usual form of the fully developed corpuscle is as shown 

 in figs. 31 and 27, the parts of the circlet becoming cylindrical 

 or bacillar ; and one can hardly doubt that they are destined to 

 be thrown off for reproduction. In their size and whole 

 appearance they agree with the above-mentioned smallest 

 bacillar corpuscles. Forms such as figs. 29 and 32 are more 

 rare, and are produced, as we may ascertain by turning and 

 twisting the object, by the portions of the circlet being pressed 

 closer together. We may always distinguish in them the 

 individual globular or bacillar parts when we succeed in placing 

 the corpuscle upon the vertex which has no circlet. In the 

 shaft of the larger and especially of the clavate specimens, we 

 observe a fine streak, the indication of a central canal, as 

 appears with certainty from cases such as fig. 30. Not unfre- 

 quently also we have forms such as fig. 26, in which the 

 main outline is surrounded by a very pale external contour, 

 and the appearance is produced as if the rod were a larger 

 cavity. Figs. 33, 34, 35 show rare irregular structures. Thus 

 in fig. 33 we see a sprout in the neighbourhood of the non- 

 circleted end ; in fig. 34 a piece of the circlet has been pro- 

 duced in the prolongation of the axis of the shaft ; and in 

 fig. 35 the circlet has been produced above its usual point of 

 attachment. 



In all the samples of mud from the Adriatic which contain 

 Bathyhius and the coccoliths, rhabdoliths also occur in count- 

 less quantities, so that a complete view of them may be 

 obtained in almost every microscopic portion. They are just 

 as well preserved as the coccoliths in the elevated deposits of 



