and two Esperiada3y/-o»« the West Indies, 271 



comes from tlie coast of Caracas' (Grundz. Spong. Faun. Atlant. 

 Geb. 1870, p. 60) ; but no figured illustration of this is given. 

 It is marked hj ISchmidt " nova species,'''' yet appears to have 

 been figured bj Dr. Bowerbank in the ' Philosophical Trans- 

 actions ' of 18(32 (pi. 30. fig. 7), and called Ectyon sparsus by 

 Dr. Gray in 1867 ; so Schmidt's name of 1870 for this sponge 

 is not wanted. 



In Dr. Bowerbank's ' Monograph ' it is given as a type 

 specimen of his genus Oplilitaspongia {pirXirr]'^, armed?), 

 wherein the sj)icules are confined to the external surface of the 

 kerataceous fibre, " exterspiculate " (externo-spiculate ?) , in 

 contradistinction to the foregoing genus Chalina, where the 

 spicules are e>ii«Ve/y " interspiculate " (introspiculate?), illus- 

 trated in the iy^Q specimen Chalina oculata, rig. 262. 



Nothing can be more natural or more distinct than these 

 two characters for these two kinds of sponges respectively ; 

 yet, immediately after making the distinction, Dr. Bowerbank 

 calls one of the. commonest opalitous sponges on this coast 

 {HaUchondna seriata, 3 o\\ns,to\\) " Chalina seriata^^ (fig. 287), 

 thus upsetting the ocular demonstration by untrustworthy 

 mental reflection. 



Schmidt, too, because the tricurvate or bow-like spicule is 

 present in this sponge, would place it among his Desmacidinae 

 (Atlant. Spong. Faun. p. 76, note, & p. 77), Avhen it would 

 come, together with Dr. Gray's Esperiadte, in his second sub- 

 section, viz. Spiculospongiaj, perhaps near Dictyocylindrus 

 (p. 519, J. c.) ; but Dr. Gray has more properly put it with his 

 Uphistospongia^ (Oplilitaspongia, Bk.), in his first subsection 

 under the second order of Keratospongias, or horny sponges, 

 with the name of Seriatula seriata (p. 515, 1, c). I say '^ more 

 properly," because it is much more horny than spiculous or 

 siliceous, which is the opposite to tlie Desmacidinaj. 



Perhaps the most useful primary division of the Spongiadje 

 may be based on the rigidity or supporting-power of the 

 skeleton-structure, i. e. in short, on the skeleton, thus : — 



1. The rigidity of the skeleton dependent on a predomi- 

 nance of the sarcodal over the siliceous element. Com- 

 mencing with Verongia, Bk., in which there is nothing but 

 horny fibre. 



2. The rigidity of the skeleton dependent on a predomi- 

 nance of the siliceous over the sarcodal element. Ex. gr. 

 Dactylocalyx jmmiceus, Stutchbury, in which the horny fibre 

 is silicified. 



3. The rigidity of the skeleton dependent on a predomi- 

 nance of the spiculous over the sarcodal element. Ex. gr. 

 Acarnus mnominatiis, in which the sarcodal element is re- 



