EURETE ERECTUM. 133 



The statements given above show that the sponges here described are very- 

 similar to Eurete erectum F. E. Schulze.^ Wilson has established three subspecies 

 of this species: — iubuliferum,- mucronatum,^ and gracile.'^ One of these, E. e. 

 mucronatum, differs from the sponges above described, and also from Schulze's 

 type, and from the other two of Wilson's subspecies, by possessing oxyhexasters 

 instead of discohexasters. This difference is in my opinion of such systematic 

 importance that I consider it distinct from the other sponges placed in Eurete 

 erectum. 



.•yter the exclusion of this subspecies, Schulze's Eurete erectum, Wilson's 

 E. e. tubuliferum, Wilson's E. e. gracile, and the sponges described above, remain 

 as forms of one species. A comparison of these shows, that, although similar 

 in the main, they differ from each other in several minor points. The tubular 

 body of the sponge is in Schulze's type dichotomously branched, in the three 

 others simple. This tube is in Wilson's E. e. tubuliferum and in my specimens 

 14-17 mm. wide, in Schulze's type and in Wilson's E. e. gracile 8-12 mm. The 

 distal rays of the dermal pinules are in Wilson's E. e. gracile 50 n thick, in Schulze's 

 type and in Wilson's E. e. tubuliferum only 35-40 n. In the specimens examined 

 by me, dermal pinules occur together with distal rays as stout as those of E. e. 

 gracile and as slender as those of the other two. In my specimens the lateral 

 and proximal rays of the gastral pentactine-like pinule-derivates are considerably 

 larger than the corresponding rays of the gastral pinules proper. In the other 

 three no such difTerence occurs, their gastral pinules and pinule-derivates being 

 about as large as the gastral pinules of my specimens. The greatest differences 

 between these sponges are met with in their scopules. To facilitate a comparison 

 between the scopules of these sponges, short descriptions of them are tabulated 

 on p. 134. 



In respect to their other characters, particularly the shape and size of the 

 uncinates and discohexasters, the four groups of forms appear to agree quite 

 closely. Schulze's type was collected at Albatross Station 2819, near the Gala- 

 pagos Islands, depth 717 m.; Wilson's E. e. tubuliferum at the Albatross 

 Stations 3358 and 3359, off the south coast of western Panama, depth 875 and 

 1015 m.; Wilson's E. e. gracile at Albatross Station 3380, Gulf of Panama, 

 depth 1693 m. ; and the specimens examined by me at .Albatross Station 4622, 

 off the south coast of western Panama, depth 1067 m. The differences between 



• F. E. Schuke. Amerikanische Hexactinelliden, 1899, p. 72, t.af. 17, figs. 1-3. 



2 H. V. Wilson. Mem. M. C. Z., 1904, 30, p. 63, pi. 7, figs. 9, 12; pi. 8, figs. 1-3, 6. 



3 H. V. Wilson. Lac. cit., p. 68, pi. 8, fig. 7. 



< H. V. Wilson. Lac. cit., p. 69, pi. 8, figs, i, 5, 8, 9, pi. 9, figs. 1, 3, 5. 



