74 BUIXETIN 125, UNITED STATES NATIONAL MUSEUM. 



HEMISEPTELLA RECTANGULATA, new species. 



Plate 14, fig. 11. 

 Description.— The zoarium incrusts shells. The zooecia are distinct, adjacent, 

 elongated, rectangular, with rounded distal border. The cryptocyst is deep, granu- 

 lar, flat; the opesium is elliptical, elongated with a proximal border irregular and 

 without' symmetry; the spinous processes are short, fragile, thin, numerous. No 



dietellae. 



^ . \ho = 0.30 mm. y . \Lz = 0.47 mm. 



J/easuremente.— Opesiaj ^^ ^ ^ 20 mm. ^ooeciaj ^^ _ ^ ^2 mm. 



The spinous processes are very fragile; they little resist fossilization, but their 

 vestiges are easily observed. 



Affinities. — This species differs from Hemiseptella granulosa in its smooth mural 

 rim and its smaller micrometric measurements. It differs from Hemiseptella grandi- 

 cella in its deep cryptocyst and its smaller micrometric measurements. 



Occurrence. — Miocene (Duplin marl); Wilmington, North Carolina (rare). 



Eolotype. —C&t. No. 68494, U.S.N.M. 



HEMISEPTELLA GRANULOSA, new species. 



Plate 29, fig. 8. 

 Description. — The zoarium is unilamellar. The zooecia are distinct, separated 

 by a furrow of little depth, elongated, rectangular; the mural rim is thin convex, 

 granular; the cryptocyst is of httle depth, flat, slightly granular. The opesium 

 is eUiptical, irregular on its proxial border which is never symmetrical; the spinous 

 processes are distributed in the lower half and the proxial bundle is wider and 

 more salient. 



_ . (/io = 0.40mm. „ . (i2 = 0.70mm. 



Measurements. — Opesia , _ _ . Ziooecia , „ „ . 



^ |io = 0.20mm. [tz = 0.35mm. 



Affinities. — The micrometric . measurements are quite variable, even on a 

 simple zoarium; but the relationship of one-half between the two dimensions 

 remain rather constant. 



This species differs from Hemiseptella planulata, in which the cryptocyst is 

 also very superficial in its granulated mural rim and in its crenulated opesium. 

 It differs from Hemiseptella grandicella in its micrometric measurements, generally 

 smaller, and in its granular mural rim. 



The spinous processes are rather fi'agile; only their base resists fossilization, 

 and they appear to be grouped into three bundles. The lowest one is wide and 

 vigorous. The asymmetry of the proximal border of the opesium seems to indicate 

 that the large retractor muscle of the polypide was inserted, not in the median axis 

 of the zooecium, but in a lower comer, as in Onychocella and Steganoporella. 



Occurrence-Miocene: Near Charleston, South Carolina (very rare). 



Eolotype.— C&t. No. 68495, U.S.N.M. 



HEMISEPTELLA PLANULATA. new species. 



Plate 29, figs. 5, 6. 

 Description. — The zoarium incrusts shells {Pectunculus). The zooecia are 

 distinct, elongated, with adjacent mural rims, hexagonal, ogival; the mural rim is 

 thin, little salient; the cryptocyst is little deep, large, flat. The opesium is ogival or 



