528 DR. J. E. GRAY ON SPONGES. [May 9, 



gated cylindrical thread-like spicules placed in a longitudinal, trans- 

 verse, and oblique direction, crossing each other, and forming a more 

 or less regular network. Sarcode scattered with stellate spicules, 

 with the rays more or less divided. 



A. Tube formed of longitudinal and transverse bundles of filiform 

 spicules, intersected with more slender oblique series of spicules, 

 and strengthened externally with transverse or oblique raised 

 ridges, the upper ridge forming a fringe between the end of the 

 tubes and the irregularly netted lid; the base of the tubes sur- 

 rounded with free filiform spicules, barbed at the end, 



1. EUPLECTELLA. 



The tubes regular, gradually wider above, formed of regular 

 longitudinal and transverse bundles of filiform spicules, which are 

 crossed in an oblique direction with more slender fascicules or sepa- 

 rate filiform spicules, and strengthened externally with transverse or 

 oblique elevated ridges ; the upper ridge forming a fringe at the top 

 of the tubes, between the edge of the tubes and the irregularly netted 

 lid. Sarcode thin, studded with many-rayed stellate spicules, with 

 long simple or trifid rays, or with short rays divided at the end into 

 several converging rays, forming a bell-shaped series. 



The fringe on the end of the tube, between it and the lid, is only 

 found in the perfectly grown sponges ; it is very small in the speci- 

 mens of £". aspergillum that are not quite of the normal form — that is, 



I certainly believe them to be) of the Jardin des Plantes are very closely allied. 

 It is not easy at first to catch a good micn^scopic character. Still there is a dif- 

 ference in the form of the small spicules especially. These two species are, hovF- 

 ever, utterly different from our Euplectella aapergillum. It would he impossible 

 to put the three even in the same genus. In the French species the network of 

 the wall is formed entirely of perfectly free spicules, very long, simply interwoven, 

 never anastomosing, held together by sarcodic sui)stance alone, and perfectly 

 easily shaken separate by a needle or a hair-pencil in a drop of water. The spi- 

 cules are exactly of the same type as those of Hyalonema, and are netted together 

 precisely in the same way ; in fact the French species would fit much better into 

 the genus Hyalonema than into Euplectella. They will not go into either genus, 

 however, and either you or I must concoct a special generic name for them. 



" Eup. aspergillum, again, reminds one strongly of the woi k you must have often 

 seen— ships, baskets, &c., made of spun-glass, by heating and netting it in and 

 out in all directions, attaching constantly the various points of contact. Thus, 

 while aspergillum is made quite rigid, the French species are absolutely flexible, 

 only firm enough to maintain their form. 



" It seems to me that we have now a series forming a very remarkable group, 

 graduating through Aphrocallistes}, Hyalonema, the French genus, Euplectella 

 {aspergillum and cucumer), into Iphiteon and Dactylocalyx. In these the form is 

 very different certainly ; but the general plan of the small free spicules is the 

 same, and the interlacing siliceous tubing is very much as in Eup. aspergillum. 



" Schultze's proposed group ' Lophospongiae ' cannot stand. It is founded upon 

 the long free spicules merely, and would only contain Hyalonema and Euplectella, 

 excluding Apla-ocallistes and the French genus, which seem to me most charac- 

 teristic members of the series. 



" By-the-by could you give me a shred of Jphrocallisles, I should like to com- 

 pare the small spicules." 



