145 



that C. Spaskii has been recorded as occurring on the "Silurian" rocks 

 of that island, by Dr. G. J. Hinde in a paper " On the Structure and 

 Affinities of the Family of the Reoeptaculitidfe," &c., in the Quarterly 

 Journal of the Geological Society of London for 1884. 



PORIPERA. 



AULACOPELLA WiNNIPEGBNSIS, Rauff. 

 Plate 16, figs. 1-3. 



Aulampella Winnipegensis, 'RaaS 1895. Pateontographioa, (Stuttgart) vol. 



XLIII., p. (393) 269, pi. 24, figs. 4-6, and 

 fig. 124 on p. (394) 270. 



Cat Head, Lake Winnipeg, D. B. Dowling and L. M. Lambe, 1890 : 

 one specimen, the type of the species. 



The following is a free translation, which has been revised by Dr. 

 RaufF, of the original description of A. Winnijxgensis, with the references 

 to the figures altered to suit those in this publication. 



This remarkable sponge is distinguished by its singular form from all 

 other Aulocopidfe, and in that respect stands in the same relation to 

 them as the Cretaceous Siphonia {Hallirhoa) costata does to the other 

 Siphonise. 



Plate 16, fig. 1, shews the upper pide of the fragment, whose boundary 

 on the right hand side is formed by the broken surface. The smooth 

 parts are the mineral fillings up of originally empty spaces ; p is the 

 Paragaster, while G 1, G 2, and G 5, are mineral wedges, shaped like the 

 segments of an orange, whose inner edges are almost parallel to the 

 longitudinal axis of the sponge, in an almost perpendicular direction 

 from the summit to the base. The under side of the sponge is concave 

 (as seen in fig. 9 on the next page) whereas the summit is convex. 

 Between the wedges of sediment (G 1, G 2, and (J 5) is situated the 

 body skeleton," which is divided into a number of strong ribs or rays, 

 traversed by thick, arched exhalent canals (aporrhysen) which appear 

 upon the outer surface of the strongly weathered and probably worn 

 fragment (Plate 10, fig. 1, as interrupted grooves. 



A vertical section through the middle of one of the rays is shown in 

 the woodcut (Fig. 9), which represents both the vertically fractured 

 surface and a section through the longitudinal axis 'of the ' Paragaster. 



