310 Mr. H. J, Carter on Sqnamulina scopula, 



Let us direct our attention to a description of the latter first, 

 as being the most interesting form of the two species. 



Squamulina scopula, mihi. PI. IV. figs. 1-11. 



Test white and hollow, consisting of a pedestal (fig. 3 a) and 

 columnar portion {hbb), the former plano-convex and the latter 

 obversely conical, terminating in a brush-like bunch of spi- 

 cules iff). Pedestal subcircular, more or less raised, closed 

 below by a discoidal portion, which, stretching across its base, 

 forms the point of attachment between the animal and the 

 fucus or object on which it may be located ; open above, 

 where it joins the pointed end of the columnar portion. Co- 

 lumnar portion erect, conical, with the pointed end down- 

 wards, consisting of a neck (d), body (c), and head (e) ; neck 

 contracted, more or less ligamentous, connecting the lower 

 extremity of the column with the summit of the pedestal ; 

 body increasing in size upwards, and formed of two or more 

 dilatations ; head inflated, and bristled all over with sponge- 

 spicules. The whole composed of fragments of hyaline colour- 

 less quartz, mixed with sponge-spicules and a small portion of 

 calcareous matter, cemented together by a chitinous substance ; 

 tessellated and almost smooth below, becoming rougher up- 

 wards, until the whole head is obscured by a heterogeneous 

 mass of projecting spicules and other like bodies, obtained in- 

 discriminately from all the sponges of the locality, both sili- 

 ceous and calcareous, arranged in a spreading form obliquely 

 forw^ards, not unlike the fibres of a little broom, Avhence its 

 specific designation — but where the spicules are capitate and 

 not pointed at each end, having the heads outwards • grains of 

 quartz, for the most part, so minute and numerous that, like 

 pounded glass, they cause the test to present a white colour 

 when dry, wdiich, of course, becomes greyish in water. Chiti- 

 nous substance or basal cement supporting the arenaceous 

 particles of the test outside, and inside forming a smooth sur- 

 face, which lines the chambered cavity of both pedestal and 

 column ; thickest, and even fibrous, about the lower end of the 

 column, where it connects the latter with the summit of the 

 pedestal, and where (if not always, for a minute distance) it, in 

 many instances, is uncovered by the arenaceous coat (fig. 4 «), 

 obviously for giving that latitude of movement to the column 

 upon the pedestal which enables the former, when fresh or 

 wet, to be bent down almost at right angles to the pedestal 

 without breaking (fig. 2 a), but, on the contrary, with the power 

 of regaining its erect position by the resilient nature of the 

 chitine, here presenting a fibrous structure, perliaps in tlie 



