CLIMACOSPONGIA. — RBNIEEA. 19 



angles ; but their arrangement seems to be irregular, as in some places they are 

 nearly in juxtaposition, whilst in others they are 1 mm. apart. 



The appearance of a vertical section of one of these sponges might, at first sight, 

 be easily mistaken for that of a tabulate coral, the vertical spicules representing the 

 walls of the coral, and the transverse spicules the tabulae. The preservation of the 

 form of this sponge is very remarkable, as there is no indication that the spicules 

 were held together otherwise than by the sarcode. It is possible, however, that 

 other and smaller spicules may have been present; for the large acerates do not 

 completely fill the apertures in the silicified matrix, and some of the reddish material 

 present may be derived from the solution and replacement of smaller spicules. 



Distribution. Silurian : Perry County, Tennessee. Judging from the mineral con- 

 dition of the specimens, they seem to have been derived from the same strata of the 

 Niagara series which have yielded numerous specimens of Hexactinellid sponges 

 belonging to the genera Asttjlospongia, Astrceospongia, and Palceomanon ; and it is 

 interesting to discover a true Monactinellid sponge in the same low geological 

 horizon with these forms. 



Genus LASIOCLADIA, Hinde, gen. nov. 

 Lasiocladia compeessa, Hinde, sp. nov. (Plate I. fig. 2.) 



The single example of this sponge is of an elongate compressed form, 36 mm. 

 in length by 12 mm. in width, and appears to have formed part of a branching 

 sponge. This fragment is composed of stout, straight, acerate, fusiform spicules, 

 pointed at both ends, which are loosely arranged together in a generally upward 

 and outward direction. Here and there sheaves of spicules project very prominently 

 outwards. The spicules appear to be generally equal in size ; the longest measured 

 is 5 mm. by "25 in width. 



The specimen is preserved on the surface of a fragment of olive-green shale. A 

 few spicules only now remain ; and these are in the condition of crystalline calcite. 

 The larger portion of the specimen merely shows the empty well defined moulds of 

 the spicules in the shale, which, in the space occupied by the sponge, is of the rusty 

 tint usually present where siliceous spicules have been dissolved. 



Distribution. Lower Devonian : Jemelle, Belgium. 



Genus RENIERA, 0. Schmidt, 1862. 

 Reniera? Caeteri, Hinde. (Plate I. fig. 8.) 



1879. Spicule "^ of a Renierid Sponge, Carter, Ann. & Mag. Nat. Hist. ser. 5, vol. iii. p. 144^ 

 t. 21. f. 11. 



Spicules smooth, cylindrical, with rounded obtuse ends ; for the most part with a 

 straight central portion, and with both ends sharply incurved, but occasionally gently 

 curved throughout. Average length 1 mm., width -146 mm. 



D 2 



