442 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



DESCRIPTIONS OF GENERA AND SPECIES. 



CAMBRIAN. 

 HAGUIA n. gen. 



Spherical bodies without any central axis or opening; with irregular 

 lacuna? or canals separated by irregular walls of varying thickness that 

 are built up of minutely granular carbonate of lime. The outer wall is 

 perforated by the apertures of the numerous canals. 



The genus is based on small spheroidal bodies that occur on slabs of 

 limestone scattered among the fragmentary remains of trilobites (Ptycho- 

 paria (X.) wisconsensis, P. (?) diademata) and the two valves of Billingsella 

 pepina. The transverse sections recall at once sections of Protopharetra 

 densa Bornemann, 1 but there is no central axis or cavity. Dr. Bornemann 

 regards Protopharetra as a lower stage of development of Archseocyathus 

 forms, but Dr. Hinde is inclined to consider it as a distinct generic type. 2 

 The form now under consideration is clearly distinct from the cup-shaped 

 and branching forms of the Archseocyathina? and evidently the simplest 

 type of the family. In fact, were it not for the absence of spicules and the 

 presence of a canal system, somewhat like that of Protopharetra densa, 

 I should refer it at once to the spong-es It is on the border land between 

 the corals, as represented by the Archpeocyathinse, and the sponges, with a 

 tendency to the latter, which would have placed it among them previous 

 to Dr. Hinde's studies. 



Haguia spelerica n. sp. 



PL LXIII, figs. 6, 6a. 



Small spherical bodies, varying from 2 to 8 mm. in diameter, formed 

 of minutely granular carbonate of lime. The irregular laminae or canals 

 are filled with crystalline calcite. The canals penetrate the outer wall 

 and give the outer surface a roughened appearance, owing to the irregular 

 disposition of the openings. In one section there is a rough radial arrange- 

 ment of the canals, but in several others there is no trace of any regularity. 



'Nova Acta, Leop.-Carol. Deutscher Akad. Naturforscher, Vol. LI, Pt. I, 1886, PI. yiH, fig. 8. 

 2 Quart. Jour. Geol. Soc. London, 1889, Vol. XLV, p. 136. 



