1867.] DR. J. S. BOWERBANK ON HYALONEMA MIRABILE. 19 



his former opinion that Hijalonema belonged to the " Barked ^/cyo- 

 naria," and announces his beHef tliat it should be arranged with the 

 Zoanthidce. 



In the Society's 'Proceedings' for 18G4, p. 265, M. Barboza du 

 Bocage, Director of the Museum of Natural History at Lisbon, has 

 described a specimen of Hijalonema, which was found off the coast 

 of Portugal, near the mouth of tlie River Sado. This specimen 

 does not appear to have had any portion of a basal sponge appended 

 to it. The author designates the protuberant organs on the coria- 

 ceous coat of the spiral column as polypes ; and describes what he 

 conceives to be a row of twenty tentacles around the central orifice, 

 and a second circle within the first one of conical elevations which 

 appear to him to be rudimentary tentacles, which he describes thus : 

 — " Les tentacules sont de forme triangulaire, comprimes des deux 

 cotes, a bords parfaitement lisses, et a pointe mousse et arrondie. 

 Ceux du premier rang sont plus larges a la base; et leur bord an- 

 terieur est plus convexe, et en forme de bourrelet arrondi." 



The author subsequently obtained two other specimens of the 

 same species, and described them in the same work for November 

 1865 : in p. 663 he writes : — "Quoique I'hypothese du parasitisme 

 des polypes soit aujourd'hui en faveur, soutenue qu'elle est par de 

 grandes autorites scientifiques, les rcsultats de mes observations sur 

 les specimens du Portugal me semblent plus favorables a I'hypothese 

 contraire." The author then proceeds to give the reasons for this 

 conclusion under five separate heads. 



The observations of M. Barboza du Bocage do not throw much 

 light on the subject of the disputed nature oi Hyalonema; and the 

 proofs he offers under five separate heads go rather to prove the 

 spongeous nature of Hyalonema than its polypiferous nature. In 

 no. 1 he merely states that no spongeous base has been found on the 

 Portuguese specimens ; but this may also be stated of the greater 

 number of specimens from Japan. He also states, in no, 2, that the 

 corium polypigerum in one specimen from Portugal envelopes the 

 whole of the axis entirely, from the smallest extremity, for two- or 

 three-fifths of its length. And this is just the condition of the speci- 

 men, supposing its lower portion to have been enveloped by a basal 

 spongeous mass, as is the case with the most perfect specimens from 

 Japan ; and the gradual diminution in the size of the oscula (poly- 

 piferous orifices of the author) is quite in accordance with their cha- 

 racters as oscula of an extended cloacal appendage to a sponge of 

 such a structure. In no. 3 the author describes the structure of the 

 corium polypigerum, or coriaceous bark of Gray, in terms which 

 apply equally well to the similar parts of Hyalonema mirahile, in 

 which siliceous spicula are also abundant, intermixed with extraneous 

 particles of sand ; but the intermixture of the latter would greatly 

 depend on its local surroundings while living. In no. 4 the granu- 

 lated appearance of the surface of the corium is described as "due 

 to the presence of an infinite number of regular spicula dispersed in 

 masses and bristling with points." And in no. 5 he states that each 

 polype is sustained by a siliceous structure of filiform spicula, disposed 



