72 BULLETIN 96, UNITED STATES NATIONAL MUSEUM. 



Genus HOLOPORELLA Waters, 1909. 



3909. Holoporella Waters, Reports on the Marine Biology of the Sudanese 

 Red Sea, etc., pt. 12. The Bryozoa. Journal Linnean Society, Tion<lon, 

 vol. 31, p. 159. 



The lower lip of the aperture is more or less straight; the oper- 

 culum has the muscles attached near the border, sometimes with a 

 ridge (for the attachment of the tentacular sheath) running inwards. 

 The ovicell is a widely open cap. There are usually oral and 

 vicarious (interzooecial) avicularia, and the mandible of one of the 

 two usually has a small pi'ojoction from the base or columella. 

 (Waters, 1909.) Spines. 



Genotype. — Holoporella {Cellepora) descostilsi Savigny-Audouiu, 

 182S. 



Range. — Claibornian-Eecent. 



The genus Holoporella is represented in the Claibornian, Jack- 

 sonian, and Vicksburgian of the Southern States by 12 new species. 



ACANTHIONELLA, new genus. 



{Akayithos, spine.) 



The apertura is oval and bears a long lyrule. The frontal is a 

 very thick olocyst, in which are lodged some avicularia. The ovicell 

 is hyperstomial. It is lodged in the thickening of the frontal of the 

 distal zocecia. It opens into the peristomie. 



Genotype. — Acanthionella {Escharifora) typica Gabb and Horn, 

 1862. 



Range. — Maastrichtian-Claibornian. 



This genus differs from Kleidionella in the presence of a lyrule 

 and the rarity of cumulate zocecia. 



KLEIDIONELLA, new genus. 



{Kleidion, small key, referring to the form of the apertura.) 



The apertura is oval. The frontal is a very thick olocyst. The 

 ovicell is hyperstomial and lodged in the olocyst of the distal zooecia. 

 It opens into the peristomie. There are some small and some large 

 interzooecial avicularia. No lyrule. 



Genotype. — Kleidionella grandis^ new species. 



Range. — Claibornian- Vicksburgian. 



The abundance of cumulate zooecia and the absence of lyrule dis- 

 tinguishes this genus from the preceding one, Acanthionella. 



KLEIDIONELLA GRANDIS. new species. 

 Plate 0, tigs. 9, 10. 



Description. — The zoarium is very large, compressed, formed of 

 bifurcated fronds almost in the same plane, attaining toward the 



