and Acapulco Sponges. 359 



the hard objects (empty shells, &c.) among which the sponge 

 may be growing (PI. XII. fig. 22) ; terminal expansions of 

 the processes charged with the flesh-spicules of the species, 

 into which the " white line " in the process, consisting of 

 a bundle of skeletal spicules, is spread out. Spicules of 

 four kinds, viz. : — 1, skeletal, acuate, smooth, straight or 

 very slightly curved, obtuse and almost imperceptibly inflated 

 at the big end, then as slightly constricted and followed 

 by a fusiform shaft, which terminates gradually in a round 

 point in the largest and in a sharp one in the rest, about 

 138 by 2^-1800ths inch in its greatest dimensions, but of all 

 sizes under this measurement ; 2, flesh-spicule, globostellate, 

 4-1800th3 inch in diameter; 3, flesh-spicule, stelliform, 

 3-6-radiate, rays long, straight, or crooked, branched or 

 spined irregularly, parting from each other directly (that is, 

 without nucleus or body in the centre, thus opposed to the 

 "globostellate" form), about 10-6000ths inch in diameter 

 (PI. XII. fig. 22, d) ; 4, flesh-spicule, minute, sexradiate, 

 body globular, rays straight, ending respectively in globular 

 inflations, which are microspined, about 3-6000ths inch in 

 diameter (fig. 22, e). No. 1 is cliiefly confined to the radiating 

 bundles which form the skeleton ; nos. 2 and 4, in great abun- 

 dance, chiefly to the circumference, among which no. 3 is 

 sparsely scattered. Size variable, according to extent of deve- 

 lopment ; the largest specimen about an inch in diameter ex- 

 clusive of the circumferential filaments. 



Hob. Marine. Growing plentifully among the detritus of 

 the sea-bottom in 4-9 fms. 



Loc. Acapulco. 



Ohs. This sponge in structure, spiculation, and colour is 

 precisely like Donatia lyncurium^ but differs from it in its 

 mode of growth, which looks like a globular form that had 

 been shattered by some explosive force in the centre (PL XII. 

 fig. 22, a a). Frequently it presents a floral or cup-like form, 

 erect or inverted, with a naked central portion like a pistil in 

 the centre (fig. 22,/*). The filaments from the circumference 

 seem to serve the purpose of propagation as well as attach- 

 ment. 



General Observations. 



As Donatia lyncurium appears to be a world-wide species, for 

 .1 havemyself had specimens from GreatBritain(this place), the 

 West Indies ('Argo' expedition), the Cape, Mauritius, and 

 South Australia, independentlyof the other places in which it has 

 been found, whose difierences in hardly any instance are suffi- 

 cient to justify a multiplication of species, although they may 



25* 



