HYDROCORALLINES AND STROMATOPOROIDS. 



227 



Distichopora and Allopora being both represented by Tertiary forms. 

 There are also certain Cretaceous fossils, at present imperfectly 

 known, which, according to Moseley, are probably referable to this 

 group. The most ancient allies of the Stylasterids, however, would 

 appear, from the researches of the present writer, to be the singular 

 Triassic fossils for which Professor P. M. Duncan founded the genera 



'0. 





A 



Fig. in. — a, Vertical section ot the ccenosteum of Allopora, sp., showing the reticulate cceno- 

 sarcal tissue and its canals, greatly enlarged. The section traverses a gastropore, which is seen 

 to be occupied below by a reticulate " columella " (s). b, Horizontal section of the same, greatly 

 enlarged, intersecting one of the systems of zooidal tubes : s, Columella of the gastropore cut 

 across ; d, One of the dactylopores cut across, c, Portion of the surface, enlarged, showing a gas- 

 tropore {g) surrounded by its circle of dactylopores (d). (Original.) 



Syringosphcera and Stoliczkaria. 



The fossils included in these 



genera are known as " Karakoram stones," and are found in strata 

 of supposed Triassic age in the Karakoram Mountains, in Kashmir. 

 They are spheroidal or spherical bodies (fig. 112) which vary from 

 an inch or less up to two inches or more in diameter, and which, in 

 unworn specimens, exhibit a warty, verrucose, or granular surface. 

 The surface also generally exhibits rounded pits or pores, which may 

 be uniformly distributed, or which are specially developed along 

 the equatorial diameter of the fossil. There are no traces of any 

 mark of attachment, and the organism must have been free. The 



1 In 1865 Professor Reuss published descriptions and figures of some fossils 

 from the Alpine Trias, for which he proposed the generic name of Heterastridium 

 (Sitzungsberichte der Wien Akad. Bd. 51, p. 385, Pis. I. -IV., 1865). It is clear 

 from these that Heterastridium is very closely allied to Stoliczkaria, if not abso- 

 lutely identical with it. In case of the identity of these two genera being estab- 

 lished, the name of Stoliczkaria will have to be abandoned in favour of that of 

 Heterastridium, the latter having been published first. 



