16 UNDESCRIBED ZOOPHYTES FROM THE YORKSHIRE CHALK. 



so common in the chalk near Bridlington, which may perhaps 

 account for its not having been before noticed. 

 11 12 13 



The annexed {Jig. 11.) will give some idea of its general 

 form. The specimen drawn {Jig. 12.) is one which was 

 found on the scar, and having been water-worn and weathered, 

 shows the internal structure; the figure, which is a little 

 magnified, displays the fibrous structure rather more plainly 

 than is seen by the naked eye, but when a lens is applied, 

 the radiating structure becomes very apparent. The struc- 

 ture of the spines is very singular ; at the base, they seem 

 composed of an aggregation of little spiculae, which after- 

 wards are so arranged as to give the appearance of a series 

 of furrowed, pointed scales. Fig. 13. represents the lower 

 part of one of the spines very higly magnified. 



The covering of the body is of a peculiar character; in 

 some places it appears similar to that of many other sponges, 

 marked with indefinite depressions ; in others, there are very 

 decided oval notched or jagged plates, most of which overlie 

 one another ; this arrangement is generally seen most dis- 

 tinctly in the neighbourhood of the spines. Fig. 14 repre- 

 14 ^^^^. sents a portion of the covering very highly 



magnified. From the singularity of this 

 appearance, the animal might almost be 

 supposed to belong to a very different class 

 from that of the sponges, and the associa- 

 ted genera ; so at least it appeared to me, 

 till, being anxious to see more of the in- 

 ternal structure, I had the specimen cut through, just below 

 the plates figured in the last diagram : an irregular fibrous 

 structure then became visible, similar to that shewn in {Jig. 

 12.) with the exception of the radiated appearance : this dif- 

 ference however may be accounted for by its being a cross 

 section. Under these circumstances, as the spongy structure 

 appears to be constant, while the plated appearance is not 

 so, I have placed it amongst the sponges till it shall have 

 been examined, and its place assigned by some more ex- 

 perienced naturalist. 



