Mr. H. J. Carter on the Gummineaj. 27 



have I become aware until just now that I had such an im- 

 portant group of sponges to study ; while, as I cannot help 

 thinking that there must be more species than Halisarca Du- 

 jardinii to be found on our coasts, so I hope to meet with not 

 only this but other species of the family here in a living state, 

 through which I may, by experiment, be able to add something 

 more satisfactory to our knowledge of their intimate structure 

 than we at present possess. 



Aided by Schmidt's figures and descriptions of the last 

 species, which he has published (Atlantisch. Spongienfaun. I.e.), 

 I now plainly see, from mounted specimens, that the incrusting 

 cartilaginous sponge which I found associated with the speci- 

 mens of Polytrema on a crab-claw kindly given to me by Dr. 

 Carpenter, and noticed in the Annals (vol. v. p. 392, 1870), 

 charged with minute stellates and long, pin-like spicules, bearing 

 a " close alliance to Tethya lyncurium" is as closely allied to 

 the incrusting species of Gummina called by Schmidt Colum- 

 nitis squamata, described and figured in the Atlantish. Spongien- 

 faun. &c. (p. 25, Taf. v. figs. 3 & 4) ; while the figured section of 

 this Gummina, in spicules and structure, is almost identical with 

 a vertical section of the circumference of Tethya (Donatio) lyn- 

 curium. In short, both species are but repent forms of Donatia, 

 which, although for the most part (but not always) assuming a 

 globular form , is, in the structure of its cartilaginous circumference 

 and spicules, more nearly allied to the species of Gumminea3 

 just noticed than to any other form of sponges yet described. 

 Then, too, we cannot help seeing the intimate relation which 

 subsists between these sponges and the Suberites, e.g. Cliona 

 celata, var., Rajihyms Griffithsii, Bk., &c. ; and thus the value 

 of Schmidt's grouping Donatia (Tethya) lyncurium and the 

 latter sponges &c. under the heading " Suberitidinse " (Atlant. 

 Spongienfaun. &c. p. 79) becomes apparent. 



In this category will also have to come several specimens in 

 the British Museum when I have time to illustrate and describe 

 them, the species (indicated by their spicules) which appear 

 in Dr. Bowerbank's illustrations of the Hexactinellid sponges 

 mentioned, and no doubt many others which will sooner or 

 later come to notice — all showing that this will one day form a 

 very large and important group among the Spongiadse. 



With reference to my statement (Annals, 1872, vol. x. p. 47) 

 that Schmidt's Halisarca guttula appeared to me to be a com- 

 pound tunicate animal and " no sponge at all," I would add 

 that later examination of the Gumminege shows me that such 

 an assertion has yet to be proved. Undoubtedly, when the 

 calcareous sphasro-stellates are dissolved out of some incrusting 

 species of Compound Tunicata, the embryos of the latter have 



