548 ' HYATT'S REVISION OF THE 



Hircinia arbusculum Sclim. (Mss.) 



I find a specimen in the Museum of Comparative Zoology, named by Schmidt Hh'clnia 

 arhusciilum. It seems to be a good species, and therefore I adopt the name, although I 

 can find no corresponding description, or even mention of the specimen in Schmidt's works. 

 The half dozen specimens examined were all from Kingsmills Islands. They are composed 

 of irregular, somewhat flattened and constantly anastomosing branches. The surface is 

 finer and smoother than is customary in Hircinia camjjana in the most extreme variations. 

 The skeleton corresponds to the surflice, and is also extremely fine, as compared wdth the 

 last mentioned species. The color of the dried specimens is light, as in H. campana, but 

 the parasitic alga was not present in the single specimens examined with the microscope. 



Hircinia acuta Hyatt. 



Polytherses acuta Duch. et Mich., Spong. de la Mer Caraibe, Verhand. Maatsch. et 

 Wetensch., Haarlem, 1864, 21-2, p. 72, pi. 13. 



This form (PI. xv, fig. 20) is distinguishable from others by the large size of the project- 

 ing fibres, the thick, tough skin covering them, and the large size of the sj)aces between 

 the spinous projections. The form of the specimens examined was rotund, the top alone 

 occupied by the numerous excurrent orifices, which were gathered together in one or two 

 sieve-like patches. The sunken spaces between the spines are from 5 to 15 mm., or even 

 20 mm. in diameter. 



This is one of the so-called Logger-Head Sponges, and emits during the process of mace- 

 ration or drying an almost imbearable stench. The largest seen, according to Dr. Palmer, 

 was about four feet in diameter and one foot high. The fibres are not at all elastic, and so 

 loosely interwoven that when artificially macerated, the skeleton w'ill entirely melt away if 

 not closely watched and delicately handled. The specimen figured, PL 17, fig. 26, could 

 have been all washed away by pressure, so soft were the fibres after forty-eight hours' im- 

 mersion. When being dried they must be constantly turned, or they will soften, looking 

 like melted rubber, according to Palmer, and lose entirely their normal form. Color when 

 living, according to the same observer, very dark gray externally, and black internally. 

 The dried specimens become much lighter, a dark drab of a purplish shade. Intei'nally 

 this sponge is remarkable for the large size and number of the canals, which are not indi- 

 cated upon the surface, and which render the whole structure very light. Habitat, reef, 

 in 8 feet of w^ater. 



Loc, Nassau, in Soc. Coll. 



Variety Jilamenta. These specimens I at first supposed to be distinct, but after the mac- 

 eration of one specimen of 11. acuta I was struck by the close resemblance of the skeletons. 

 The three dried specimens examined have a very open structure, but the skeleton is so 

 completely covered by the filamentous tissue that it is hardly possible to see any part of it 

 distinctly. The interior is exceeding hollow, or rather celkdar, the hollows being separated 

 by thin walls of the filamentous tissue, within which lie the fibres of the true horny skele- 

 ton. These skeletons are therefore of the most paper-like structure and extreme porosity. 

 The primary fibres project in large tufts beyond the surface. 



Loc, Cape Florida, in Soc. Coll. 



