174 W. I. Robinson, 



1883 Calostylis Roemer. Leth. Geog., Pt. I, Leth. Pal. : 393. 

 1889 Calostylis Neumayr. N. Jahrb. f. Min., etc., Pt. 11:44. 

 1896 Calostylis Koken. Leitf ossilien : 307. 

 1908 Calostylis Giirich. Leitfossilien : 38. 



Calostylis was proposed by Lindstrom for a peculiar coral in 

 the Silurian of Gothland, Sweden. Lindstrom, Duncan, and 

 Zittel believed it to belong with the Hexacoralla, while Roemer, 

 Neumayr, and Freeh regarded it as an extraordinary develop- 

 ment of the Tetracoralla. 



Translation of the Original Description. — Composite coral. 

 Lateral buds in a single unilateral series. Septa very numerous, 

 often coalescing. Columella trabecular. Epitheca incomplete. 



In Giirich's Leitfossilien the genus is described as follows 

 (translation) : 



Horn-shaped corals of the length of a finger. Upper Silurian 

 of Gothland. They have over one hundred closely spaced septa 

 in apparently several, but really two, cycles of two lengths repre- 

 senting primaries and secondaries. The septa are perforated, a 

 character which, with this one exception, occurs only in the 

 Hexacoralla. The broad central space has a spongy pseudo- 

 [parietal] columella. The exterior has a thin epitheca. This 

 apparent analogy with the structure of the much later occurring 

 Hexacoralla may be considered as a case of parallel development 

 [Konvergenzerscheinung] within the wide realm of variation of 

 the Tetracoralla. 



The statement that this is the only Paleozoic "perforate coral" 

 is no longer true, as most of the Tabulata are more or less 

 replete with mural pores. Furthermore, Hinde (1889) described 

 genera of the family Archaeocyathidae from the Lower Cambrian 

 among which there are several "perforate" corals. ArchcBocya- 

 tJiiis (restricted) has perforated septa; Coscinocyathus has 

 perforated transverse plates; Protopharetra has porous walls; 

 Ethmophyllum and Spirocyathus have canal structure in the 

 walls. 



List of Species. 



Calostylis denticulata (Kjerulf). Genotype. 



Clisiophyllum denticulata Kjerulf. Veiviser ved geol. Excur- 

 sioner i Christiania Omega, 1865 : 22, 25. 



