474 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



of these as the basis of the following notes. Of Duncan's varieties, 

 it seems to me that magnetica, pulchella, and nobilis should be com- 

 bined with the typical form of the species; that his varieties minor 

 and nugenti should be combined under one name, nugenti, preferred 

 by me as it is desirable to preserve the record of the part Doctor 

 Nugent played in making known the fossil corals of Antigua ; and that 

 variety magnijicea should be retained without any important change. 



DIPLOASTREA CEASSOLAMELLATA (Duncan) Vaughan, typical. 



Plate 135, figs. 1, 2, 3, 4, 4a, 5, 5a, 56; plate 136, figs. 1, la, 16; plate 137, figs. 1, 2, 3, 



4, 4a, 5. 



Plate 135, figure 1, illustrates, natural size, a polished surface of a 

 typical specimen in Duncan's original sense; and plate 135, figure 2, 

 illustrates natural size, a polished surface of Duncan's variety nobilis. 

 Duncan did not recognize that the septa in such specimens are 

 perforate and that synapticulae are abundant. These two figures 

 will serve to validate the identifications here made, as reference to 

 Duncan's original figures will show. 



As I collected a series of specimens ranging from a solitary corallite 

 to a fully developed corallum, the development of the corallum will 

 be described. . 



Specimen No. 1.— The only solitary corallite I collected (pi. 135, 

 fig. 3) is inversely sub-conical in shape, the apex broken. It is 

 28.5 mm. tall, and is 16 by 18 mm. in maximum diameter. The 

 older calice was damaged and a smaller calice has formed above the 

 older. On the outer surface is an incomplete, finely striate pellicular 

 epitheca; subequal or alternately larger and smaller, more or less 

 interrupted, beaded costae are seen in the areas not covered by the 

 epitheca. The costal ends are joined by synapticulae, between 

 which are perforations. The wall originally is synapticulate. 

 Septal margins coarsely beaded. Primary and secondary septa 

 solid for the most part; tertiaries more perforate; quaternaries de- 

 cidedly perforate. Columella well developed; surface coarsely 

 papillary; fossa shallow. As the structural characters of this speci- 

 men are essentially identical for all other typical specimen of the 

 species, descriptions of the epitheca, costae, and intercostal synapti- 

 culae need not be repeated. 



Specimen No. 2. — In this specimen the primary corallite has given 

 rise to one lateral bud (pi. 135, figs. 4, 4a), between which and the 

 parent corallite is a slightly depressed intercorallite area. Diameter 

 of parent corallite, 24 mm. Septo-costae more or less confluent 

 and continuous, interrupted with perforations, joined to one another 

 by synapticulae; margins coarsely, rather irregularly beaded. 



Specimen No. 3. — There are seven corallites, separated by wide 

 intercorallite grooves, in this specimea. Five corallites are shown 



