98 Mr. H. J. .or 071 the 



4. Tuhella recurvata. (PI. V. fig. 7, a-Z.) 

 Spongilla recurvata, Bk., No. 20, p. 18, pi. xxxviii. fig. 10. 



Sessile, coating. Surface even. Structure fragile, crum- 

 bling. Colour brownish. Skeleton-spicule curved, fusiform, 

 abruptly sliarp-pointed, smooth or spiniferous. Statoblast 

 globular (PI. V. fig. 7) ; aperture infundibular (fig. 7, g) ; crust 

 thick, composed of granular microcell-substance (tig. 7, c?), 

 charged with inajquibirotulate spicules (fig. 7, e) consisting 

 of a delicate, straight, smooth shaft passing by trumpet-like 

 expansion into the large disk, which is circular, smooth, saucer- 

 shaped, inverted, with even margin, curved towards the 

 shaft, and abruptly terminating in the other, which is only 

 one eighth of the diameter of the disk (fig. 7, t), arranged 

 perpendicularly with the large disk resting on the chitinous 

 coat, and the small one somewhat within the surface of the 

 crust (fig. 7, e) ; surrounded by a capsule of short thick 

 spicules (fig, 7,/), consisting of a straight smooth shaft, 

 slightly inflated in the centre, and terminated at each end by an 

 equal-sized head, which is prominently umbonate, with cir- 

 cular margin regularly divided into eight conical teeth slightly 

 incurved (fig. 7, k^ I), arranged perpendicularly around the 

 statoblast, with one end free and the other adherent to the 

 surface of the crust (fig. 7,f). 



Log. River Amazons. 



Obs. This kind of capsular covering is, so far, unique, and 

 renders the whole structure of the statoblast as remarkable as 

 it is beautiful under microscopic observation. 



Parmula*. 



Gen. char. Globular or elliptical, fusiform when growing 

 round the small immersed branches of trees. Structure coarsely 

 reticulate, extremely hard and rigid, rising into thorn-like 

 processes on the surface. Colour light green. Skeleton- 

 spicule acerate, curved, fusiform, abruptly sharp-pointed, 

 smooth. Statoblast globular, large, more or less tubercular 

 on the surface ; aperture infundibular ; crust composed of 

 granular microcell-substance (PI. V. fig. 2, a), charged with 

 and surrounded by minute, spinous, acerate spicules (fig. 1,^, 

 and 2, d), limited by a layer of parmuliform spicules (fig. 2, b, c) 

 both internally and externally, the former in contact with the 

 chitinous coat (fig. 1, e), and the latter on the surface of the 

 crust t (fig. 1,/). 



* Parmula, a little round shield. 



t As these characters are taken from the only species yet known, they 

 may hereafter have to undergo alteration. 



