22r. TUK AMEUICAX MONTHLY [Aiij?.. 



all »>i wliirh. riiDt'iuUor, arc Id he found in tlu' Harliadocs dv- 

 |>oiit. lUit tlnse 1!)1 genera aro altojictlii-r too much for one ar- 

 ticle. However, they fftll conveniently into two groups in one 

 of which there are 71 jjenera. Some of these were classilied in 

 my first i)aper, hut more were not. 1 sai«l the I*erijn'hi'a (or 

 Spumellaria) contained 2() genera and I gave the names. Two 

 of those genera 1 find now are n(»t rei)resented in Harhadoes, 

 namely. .*<^»jMra(7»/-(i and Echinnclura. So that of the 71 genera 

 only IS have been touched upon, in other words 53 will hv en- 

 tirely new. Under those circumstances I think it will l>e wise 

 to begin all over again. 



Let u^ take then the 71 genera of the Spimkl'-aria, or I'kri- 

 i*VL.K\. in which the skeleton is round or disk-like an<l has no 

 large mouth orojtening and the central capsule is splurical and 

 has pores distributed all over it. 



Now these 71 genera are tlivided into o main groups, thus: 



L Sphnroidea — Spherical Shell. 



n. Prunoldea — Ellipsoidal Shell. 



III. — Discnidca Discoidal Shell. 



Taking the first in order, we have 21 genera arranged accord- 

 ing to the pre.'^encc or absence of radial s|>ines and the nuiii- 

 bi-r of sjihi-res. 



I.— SPHERICAL FORMS. 



L— Family: LIOSPH.ERIDA. No radial spine.«. 



A. — ONE Sl'HKUK. 



Tuhuli. EthmoKphsRrn. 



None. Cenosjthn I'd. 



B. — TWO SF'IIFHK.'^. 



One within capsule. Carposjjiixra. 



C. — THKKK SI'HKKES. 



One shell within caj>sule. Rhodnftjthnern. 



Two shells within cajisule. n€co!<ph(fr(i. 



D. — FOIR SPHERES. 



Two inner medullary, two outer cortical. Cromi/0'^])h(n-n. 



2.— Family: STYLOSPH.ERIDA. Two radial spines op- 

 posite in one axis. 



A. — 0.\E SI'HE1{E. 



Si>ine8 equal. Xiphofqjh<era. 



S})ine8 difTerent. Xipfioxtylus. 



