1895 THE MICROSCOPE 69 



columns, that is the horizontal rings are connected by 

 two vertical rings. Tympaniscus has six columns or 

 three vertical rings, and Tympanidium eight columns or 

 four vertical rings. The student should understand that 

 these vertical rings are incomplete, and that the little 

 columns are supposed to represent segments of such 

 rings, in other words that if vertical columns (as in Fig. 

 23) were produced and united above and below where 

 they join the horizontal rings they would form a com- 

 plete vertical ring. 



In the second division of the Nassellaria the forms 

 have a complete shell, and the shell is latticed, that is 

 has pores. Here are three orders which are distinguished 

 by the form of the cephalis or first joint. In the first 

 order, the Spyroidea, this cephalis is bilocular, that is, it 

 is divided into two chambers by a middle partition, (see 

 Figs. 24, 25). The Fam. Zygospyrida consists of those 

 forms which have only a cephalis (see Fig. 24), in other 

 words there is no second joint or thorax as it is called. 

 The genera are divided into sections by the number of 

 basal feet, the last section lacking them altogether, and 

 are still further separated by the number and disposi- 

 tion of horns or the absence of them. In the Fam. 

 Phormospyrida, besides the cephalis there is also a tho- 

 rax, that is, the shell consists of two joints (see Fig. 25) 

 the cephalis being the upper, the thorax the lower. And 

 in the Fam. Androspyrida the cephalis has an apical cu- 

 pola, or little dome at the top. 



In the second order, the Botryodea, the cephalis is 

 multilocular, that is consists of several chambers, and 

 their appearance is that of lobes, (see Figs. 26 28). The 

 forms of the Fam. Cannobotryida have only the cephalis, 

 (see Fig. 26), while those of the Fam. Lithobotryida 

 have a thorax, or second joint also, (see Fig. 27). Here 

 we meet with the distinction, mouth closed, which I 



