36 Dr. J. V. Barboza du Bocage on Hyalonema boreale. 



V. — On Hyalonema boreale. By J. V. Barboza du Bocage. 



To Dr, J. E, Gray, F.B.S. 

 My dear Friend, Lisbon, May 6, 1868. 



I have just received the interesting memoir of M. Lov^n 

 upon Hyalonema horeale^. I must confess that M. Lovdn's 

 publication has caused me some vexation, as more than two 

 months ago I prepared a similar memoir, which I have been 

 hitherto prevented from publishing by illness. Since the 

 17th of February I have been in possession of two curious 

 specimens of a Spongiad, which I immediately regarded as 

 the young of Hyalonema lusitanicum. 



I find some important diiFerences between my specimens and 

 that described by Loven. In the first place, the sponge which 

 forms the head has no apparent oscidum ; and then the sarcode 

 is covered with very complicated spiny spicules, which are not 

 noticed by Loven. 



I do not share all Loven's ideas. I cannot admit that the 

 sponge which accompanies several specimens of Hyalomena 

 from Portugal and Japan is the sponge-head of the young 

 specimens ; on the contrary, I am persuaded that the sponge 

 which persists in the adult specimens is precisely that which 

 forms the dilatation of the base, so that it is the upper portion 

 or extremity of the filaments which re- 

 mains free. The following are my rea- 

 sons : — 



1. I remarked in my two young speci- 

 mens that the large spicules constituting 

 the axis all terminate below at the same 

 level, whilst their superior extremities re- 

 main at different elevations. Now all the 

 adult specimens present this same cha- 

 racter : the filaments have their extremi- 

 ties at the same level in the part enclosed 

 in the sponge, whilst they show their free 

 extremities at different heights. I think 

 therefore that this sponge is inferior, and 

 that it corresponds to the sponge which 

 occurs at the base of the young specimens. 

 (As a matter of course, I regard the speci- 

 men figured by Lov^n as a young Hyalo- 

 nema^) 



2. The following is another argument '^f^^^ P centims ; 

 • /. p • • T diameter of the 

 m favour of my opmion. I possess a very gp^nge 17 centims. 



* [A translation of this memoir, with which we have been kindly fur- 

 nished by the author, will appear in our next Number. — ICd.J 



