414 ' PROCEEDINGS OP THE ACADEMY OF 



bear near the centre a small tubercle. The brachial pieces appear to rest 

 upon the last of the preceding series. Interradials : the interradial fields ars 

 filled with from seven to nine pieces, the first are of the same size and form 

 as the second radials ; they rise from the angular notch between the first 

 radials, and support on their upper margins two spinous pieces like the third 

 radials, with which they form a circle around the base of the vertical sides of 

 the body ; in an angular notch between the second range of interradials rests 

 one large spinous piece, this supports two or three nearly smooth pieces one 

 above the other. Interaxillary : rising between two of the first secondary 

 radials are two small pentagonal pieces, one above the other, completely en- 

 closed by the pieces of the secondary radials. Anal pieces : these are about 

 twenty in number, rising in ranges one above the other ; these ranges are not 

 quite regular, but are thrust into and interlock each other ; the pieces are 

 similar in form and size to the other pieces of the same height composing the 

 calyx. They diminish in size and number in the ranges until the field is 

 terminated by a single piece immediately below the circle of the arms. The arms 

 are thirty in number, in groups of six each ; they form a closed circle around 

 the calyx and support the vault. They appear to have been nearly circular, 

 formed of two rows of thin pieces ; the opening through the arm facets is cir- 

 cular and covered by the pieces of the summit. The summit is covered by 

 numerous small polygonal pieces differing greatly in size. Near to the mar- 

 gin and immediately above the centre of each group of arms is placed a larger 

 piece which is surmounted by a short spine ; all the pieces are well defiued by 

 a deep groove at the line of the union of the pieces. The proboscis appears, 

 (judging from two circles of pieces which are attached to our specimen), to 

 have been composed of stout small pieces similar to those forming the sum- 

 mit. The surface markings are nearly all removed from our specimen ; one 

 or two pieces of the summit are finely granulose. The epidermis bearing the 

 granula, is about one-thirtieth of an inch thick. 



Dimensions. 



Height from base to free arms '55-100 inch. 



Height from base to proboscis 1 '00-100 " 



Greatest diameter of calyx below arms 1*25-100 " 



Greatest diameter of summit 1'60-100 " 



Diameter of basal pieces '25-100 " 



Geological position and locality. Collected from a bed about six feet below 

 the hydraulic limestone, Falls of Ohio, Clark county, Indiana. It is associated 

 with the preceding species. My cabinet and that of Dr. J. Knapp, Loiiisville, 



Ky. 



Descriptions of three new species of Mollusca of the genus SPHiERIUM. 



BY TEMPLE PRIME. 



1. Spheerium meridional e, Prime. S. testa ovato-oblonga, compressa, 

 tenui, insequilaterali, tenui, transversim elegantissime striata ; intus carneo- 

 rubra maculata ; umbonibus parura prominentibus, natibus acutis, antice ap- 

 proximates, inclinatis; epidermide fusco-luteolo, nigro-maculata ; latere antico 

 brevi valde declivi, obtuso, postico subangulato, margine inferiore parum ar- 

 cuato ; dente cardinal! minirao, dentibus lateralibus valde compressis, elongatis, 

 antico majore. 



Long. \ ; lat. l-5th ; diani. \ poll. 



Hob. Panama; (Collect. Prime.) 



Compared to the Sphaerium maculatum, Morelet, of Yucatan, this species 

 differs in having a less abrupt posterior margin, its lateral teeth are larger and 

 more developed, and the shell is generally less inflated. 



[Dec. 





