New Species of Sponges. 



53 





other and unite, forming a loop. General diameter, about 

 3 to 5 centimetres. Length of root-spicules, 6 to 7 centi- 

 metre.s, Wall of body apparently thin, composed of large 

 cruciform spicules, stout at centre and tapering to sharp 

 points, and arranged in square meshes, with smaller spic- 

 ules of the same forms in the meshes. Length of largest 

 spicules and size of meshes, 1 centimetre or less. 



The structure of this sponge places it in Protospongia of 

 Salter. It is true that the species of Protospongia are not 

 known to have root spicules, but these must have been pre- 

 sent in some form, and perhaps the bundle of spicules from 

 the Meneviaii, described by Hicks as P.flahella,^ may have 

 been of this nature. 



The root of this species is very peculiar in its arrange- 

 ment. It seems to have been a cruciform spicule, of 

 which the rays were bent upward and lengthened, form- 

 ing a stalk for the sponge. This would give a firm attach- 

 ment, and adapt itself to the gradual rise of the bottom to 

 wnich the sponge was attached. The mechanical proper- 

 ties of such an arrangement of spicula are obviously well 

 suited to effect their purpose. 



Salter, in his oiiginal description of Protospongia from 

 tae Cambrian of Wales, compares it with Acanthospongia of 

 Griffiths from the Silurian of Ireland, the original specimen 

 of which ho had seen ; but says it has six-radiate spicules. 

 He also remaiks that the spicules c." Protospongia seem to 

 be all on one plane.^ P. Major of Hicks is a still older spe- 

 cies from the Lower Cambrian or Longmynd Series, and 

 seemingly of different structure and of much more open tex- 

 ture than that above described. Matthew has also noticed 

 and figured fragments of Protospongia from the Lower 

 Camlirian of St. John, New Brunswick. The present spe- 

 cies, though somewhat later in age than the foregoing, 

 has the merit of presenting a better state of preservation 

 and better illustrp*ing the general form, and moie espe- 

 cially the root-spiv.»i3s. 



1 Hicks' Jour. Geol. Sec, Vol- xxvii. 

 ■^ Journal Geol. See, VoL xx. 



