546 HYATT'S REVISION OF THE 



Dr. W. G. Farlow, the well known Algologist, has had dried specimens under examination, 

 and reports to me that he finds no sure grounds for referring them to Alg£e, or any plant 

 structure, and examinations of the Uving sponge will probably be necessary in order 

 to determine the exact nature of these threads. The extremely thin, sheet-like arrange- 

 ment of the fibrillre of the connecting fibres in many species adds to the difficulty of sep- 

 arating the filaments from the fibrillar. 



The fibres are composed of fibrillar, or threads of horny-colored appearance. These are 

 bound together in bundles to form the primary or vertical fibres, and are more or less 

 spreading, or fan-like, especially at their bases ; when modified by the connecting tissue, the 

 horizontal fibres sometimes spi'ead into comj^lete screens, even when entirely freed from 

 the parasitic filaments. Both systems of fibres are usually loaded with foreign matter, 

 and often this is so purely composed of spicules as to lead to curious blunders. Duchassa- 

 ing and Michellotti's reference of this genus to the siliceous sponges is due to this, and I 

 have seen one specimen inseparable from a true Chalina, either in the form or arrangement 

 of the spicules. The epidermis is remarkably thick, and usually loaded with foreign mat- 

 ter, but when partly free from this, or partially macerated, exhibits certain peculiarities. 

 The skin entirely covers the points of the primary fibres as a rule, but when they protrude 

 it is seen that they are often composed of several fibres, or bundles of fibrilljB. From the 

 terminations of these there spreads out an extensive epidermal network of secondary fibres, 

 the close association of which with this external membrane explains the load of foreign 

 matter which they bear. 



Hircinia campana ISTardo, Isis. 1833-34. 



Spongia cmnpana Lamarck, Anim. sans. Vert., 2d ed., vol. 2, p. 364. 



Filifera campana Schmidt, Spong. d. Atlant. Gebietes, p. 30. 



Polytherses campana Duch. et Mich., Op. cit., p. 68. 



Variety typica. The normal variety of this species is vasiform (PL xv, fig. 19). It 

 may be either ribbed externally, or smooth, with of course the exception of the projecting 

 spines composed of the bundles of vertical, primary fibres. 



Variety ^x-a Duch. et Mich. This is the same as typica, but the vase is open on one 

 side (PI. XVII, fig. 28). I have examined complete series of this and of the normal variety. 

 and though they are distinct forms, there are many intermediate forms, and one specimen 

 has one side open below, showing that it began life as variety ^x'a and ended it as one 

 of the normal variety. One specimen of this variety in Mus. Comp. Zoology, is reported 

 from 40 fathoms oft' Conch Eeef, Fla. 



Some specimens of both of these varieties have peculiar outgrowths of certain parts. 

 These may take place externally and surround the cup with a hedge of branches, or within, 

 giving rise to single projecting branches of greater or less length. Again this tendency to 

 branch may be accompanied by a thickening of the walls, which if carried out fully would 

 entirely change the hollow vase to a mass with many radiating or erect branches at the top. 

 In all of these varieties the larger apertures are within, and the smaller without. 



Variety felix. 



Polytherses felix Duch. et Mich. 



This variety is similar to the young of the last described before it begins to assume the 

 vase form. It is short and clumpy, with orifices on the upper side, which may either be 

 numerous, or single. The bundles of fibres project above the surface more than in 



