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On an Undescribed Species of Sponge of the Genus 

 Polymastia, from Honduras. 



By B. W. Priest. 



(Read June 24, 1881.) 

 PLATE XXIII. 



Some months back Mr. Curties placed in my hands a Sponge for 

 description, sent by Mr. B. Wills Richardson, found in shallow 

 water, 14 to 17 fathoms, near Belize, British Honduras, at a part 

 of the coast not previously dredged. On examination it proved to 

 belong to the genus Polymastia of Bowerbank, but to the best of 

 my knowledge it is an undescribed species. 



The generic name is derived from the Greek, ttoXvs, many, and 

 fida-TL^, a whip, scourge, or flail, from the presence of fistulse, 

 simulating those instruments more or less, projecting from the sur- 

 face of the Sponge. 



The specific name I propose is bi-clavata, for reasons which will 

 be shown further on. 



According to Dr. Bowerbank we have eight recognised British 

 species, but none of them showing the three special characteristics 

 of the one under consideration. In this, we have a Sponge which 

 may be called massive and bulbous, measuring rather more than a 

 quarter of an inch, not including the fistulse, from the summit to 

 the base, and rather larger in diameter, say, just under half an 

 inch. The outer crust, along with the inner walls and supports of 

 the sponge, as also the fistulse — in fact, the whole skeleton — being 

 composed of a beautiful network, abundantly supplied with bi- 

 clavate fusiform spicules of various sizes, averaging from the J^ to 

 •^^ of an inch, the difference in size being probably due to states 

 of development. The sarcode which fills the cavities of the Sponge, 

 as also the interstitial membrane, when present in this specimen, 

 are supplied with spicules of the same type as tlie skeleton, but 

 fewer in number, and also abundantly with equi-tridentate anchorate 

 spicules of two sizes, the larger measuring j-^oj^ of an inch, the 



