22 



GLYPTOCRINUS siphonatub, (n. b.) 



Description. Body large, broadly obovate, the greatest 

 width being above the origin of the arms ; calyx narrow below* 

 spreading gradually to the bases of the arms ; dome inflated on 

 the anterior(?) side. Arms rising from the body in pairs with 

 deep constrictions between ; arrangement and forms of plates 

 of calyx not fully determined ; those of the dome are small 

 and polygonal. 



The above description is drawn from internal casts. This 

 species differs from G. nobilii in the much greater length of 

 calyx which is not contracted in the lower part; while in that 

 species it is broad and spreading. It appears not to have had 

 a proboscis ; but in the casts there is the filling of a cavity 

 which has passed from the summit of the dome between the 

 postero-lateral arms, where it turns outwardly, as if it had 

 opened on the exterior surface in the form of an oval opening. 



Geological Formation and Locality. In rock of the age of 

 the Niagara group ; Racine, Wisconsin. Br. P. R. Hoy, T, J. 

 Male, James Hall. 



GENUS BALANOGRINUS, Troost. 

 Balanocrinus inflatus, (n. s.) 



Description. Body below the arms subturbinate, with sideg 

 somewhat inflated in the lower part ; arm bases prominent, 

 leaving deep interbrachial spaces; dome low, strongly inflated on 

 the oval side, surmounted by a slender sub-central proboscis. 

 Basal plates small, pentagonal. Sub-radial plates proportionally 

 large, hexagonal. First radials heptagonal, a little larger than 

 the sub-radials ; the form of the second and third radials un- 

 determined; the second are as large as the sub-radials; the 

 third very small. 



Interradial plates, six; the first hexagonal, as large as the 

 second radials, with two in the second range, and three in the 

 third range, uniting with the dome plates. Anal plates numer- 

 ous, form and arrangement unknown. 



The above descriptions have been drawn from the internal 

 casts of several specimens, which exhibit the divisions of the 

 plates. 



This species differs from B. sculptus, Troost; Lampterocrirw* 

 tennesseensis, Roemer "Silurian Fauna of Western Tennessee," 

 in being more distinctly turbinate or obconical ; in the deeper 

 interbrachial spaces ; and the inflation of the dome on the aa- 

 al side. 



