190 ANNAL.S Xi:\V y()ia\' MWDI'JMr OF SCIENCES' 



VII. For zaphrentoids flattened on the side of greatest curvature' 

 Simpson proposed the generic name Hoinalopliyllum, with Z. ungula 

 Rominger as the genotype. 



YIII. Grabau in 1910 proposed Heliophrentis for Silurian zaphren- 

 toids characterized by carinae. This may turn out to be synonymous with 

 Zaphreniis sens str. 



IX. Finally, the term SipJionoplirentis is here proposed for those forms 

 which like gigantea of Lesueur have numerous, well-developed tabulae 

 extending entirely across the visceral chamber, bending down marginally, 

 and, on either side of the cardinal septum, forming a series of invaginated 

 fnnnels giving a siphonofossula. There is no external vesicular zone. 

 The name Caryopliyllia has a definite, restricted sense among modern 

 authors and cannot, therefore, be applied to the forms just characterized. 

 Siplionoplirentis has for its genotype Caryophyllia gigantea Lesueur, the 

 form usually referred to as Zaphreniis gigantea from the Middle De- 

 vonian of eastern ISTorth America. In this as in the -preceding genus, the- 

 tabulae are the chief element, the septa being reduced. 



Summary of the Eevisiox of the Genus Zaphrentis 



Zaphrentis 

 (sens, lot.) 



I. Zaphrentis Eaf. and Clifford sens str. Silurian ? to Devonian. 

 Genotype : Caryophyllia cornicula Lesueur. 

 11. Caninia Michelin. Devonian to Mississippian. 



Genotype: Caninia cornucopice Michelin. Other example, G. 

 pat til a Mich. 



III. Heterophrentis Billings. Silurian ? to Devonian. 



Genotype : Zaphrentis proUfica Billings. Other example, Z. 

 simplex Hall. 



IV. Siphonophyllia Scouler. Mississippian to Carboniferous. 



Genotype : Caninia gigantea Michelin. Other example, C. 

 rornu-hovis Mich. 

 V. Hapsiphyllum Simpson. Mississippian. 



Genotype. Zaphrentis calcareformis Hall. 

 VI. Triplophyllum Simpson. Devonian to Mississippian. 



Genotype: Zaphrentis terehrata Hall. Other examples, Z. 

 centralis, E. & H., Z. dalii, E. & H. 

 VII. Homalophyllum Simpson. Devonian. 



Genotype: Zaphrentis ungula Rominger. Other example, Z. 

 herzeri Hall ( ?). 



