HYMEN JACIDOX. 71 



with it in its structural peculiarities in every part of 

 the sponge." 



2. HYMENIACIDON THOMASII:, Dow., IT, 155 ; r m, PI. 

 XXX, figs. 13 



1867 Reniera Thomasii, Gray. Proc. Zool. Soc., p. 518. 

 1870 Amorphina Thomasii, Schmidt. Spong. Atlant. Geb., 

 p. 76. 



" I received a small specimen of Nullipora poly- 

 morpha from the Rev. A. M. Norman, about one inch 

 in length, amid the short branches of which a small 

 mass, rather exceeding half an inch in diameter, of a 

 sponge of a dull ochreous yellow colour, was immersed. 

 On a microscopical examination, this proved to be 

 Hymeniacidon Thomasii, but bearing not the slightest 

 resemblance in form or external characters to the 

 type specimen described in vol ii, p. 155, and figured in 

 Vol. Ill, Plate XXX, fig. 1, Mon. Brit. Spongiadce.' 

 Although so small a specimen, the anatomical cha- 

 racters were as fully developed as in the type specimen. 

 It would appear that this species is of rare occurrence, 

 as this is the only other specimen I have seen, except- 

 ing the type. The small specimen described above 

 was dredged in "Westport Bay, Ireland, in five fathoms, 

 by the Rev. A. M. Norman." 



