Mr. 11. J. Carter on the Guramineai. 25 



If we were to see a tougli, wet, shining lump of dough lying 

 on a piece of sponge in our bath-room, there would be no hesi- 

 tation in distinguishing the two objects ; but if we were to 

 observe something like this attached to a sponge growing on a 

 rock in its natural habitat, the probability is that it would be 

 a Gummina. Such may give some idea of the typical form 

 of the Gummine^e. 



As yet only one species has been noticed on the British 

 coasts ; and that has been designated by Johnston " Halisarca 

 Dujardinii^'' after the illustrious naturalist who first described 

 and gave it the name of " Halisarca " {aXto<;, marine, and 

 o-ap^, flesh). Johnston found it in Berwick Bay, and has 

 giilen the following description of it in his ' British Sponges,' 

 published inl842 (p. 192), together with a figure (pl.xvi. f. 8) : — 



" Halisarca, Dujardin. 

 " Character. Substance fleshy or rather gelatinous^ semi- 

 transparent^ unorganized^ forming an irregular crust on the 

 objects to which it adheres. 



" 1. H. Dujardinii (plate xvi. fig. 8). 

 " Halisarca, Dujardin, in Ann. dea Sc. Nat. n. a. x. p. 7, pi. 1. fig. 5. 



^'■Hab. On the underside of stones between tide-marks, and 

 on the stalk and roots of Larninaria digitata^ common. Ber- 

 wick Bay ; Holy Island (G. J.). 



" Sponge in the form of a gelatinous crust, spreading irregu- 

 larly, about a line in thickness ; the surface even and smooth, 

 of a straw or ochre-yellow colour, mottled with little pale cir- 

 cular spots or pores, produced apparently by a deficiency of 

 colouring-matter in their places. A few of these transparent 

 spots are larger than the others ; and if the former have any 

 relation to the pores of the ti'ue sponges, the latter may be the 

 analogues of the faecal orifices. 



" This production is liable to be mistaken for one of the 

 crustaceous Compound Tunicata, or, rather, for the gelatinous 

 spawn of the naked mollusca; but a careful inspection easily de- 

 tects the difference. This exhibits no trace of any oviform bodies 

 or cellular tissue, and contains neither crystals nor spicula, but 

 is no otlier thing than a mass of irregular and granulous 

 globules, of great minuteness, that lie imbedded in a clear jelly, 

 covered over with a more consistent and coloured skin. Dujar- 

 din has ascertained that, when broken up, the separated masses 

 shoot out from their sides delicate prolongations or filaments 

 of various lengths, and slowly change their figm-e, in the same 

 manner as do the detached sarcoid pieces of the freshwater 

 sponges (see woodcut no. 9, p. 61)." 



