238 Mr. A. Hancock on the Excavating Sponges. 



throughout minutely spined ; but in some instances the spines 

 are sufficiently strong to be observed with the ^-inch object- 

 glass : the third form is -ttito ^^^^^ long, cylindrical, irregularly 

 bent or angulated once or twice, occasionally three times ; it has a 

 central angle, and is strongly spined ; the extremities are obtuse. 



Several specimens have recently occurred in oyster-shells, but 

 the locality is not known. When dry the sponge is of a yel- 

 lowish-white colour. There are both large and small papillee in 

 this species; the former are three times the size of the latter, 

 and are scattered at wide intervals among the others. 



Cliona corallinoides. PI. VII. fig. 3, 



Spicula of three kinds. The first, yV inch long, is pin-like, 

 slender, generally bent in the centre, tapering gradually to a 

 sharp point at one end, and at the other furnished with a well- 

 defined elliptical head : the second kind is scarcely one-third 

 the length of the first; it is fusiform, very delicate, and suddenly 

 bent in the centre, and when observed with the ^-inch object- 

 glass is seen to be minutely spined ; the extremities are sharply 

 pointed : the third form is minute, being only -^rwo-o ^^^^^ l^''^9 > ^l 

 is spinous, with the extremities obtuse, and is generally zigzagged, 

 having three angles, one being in the centre. 



A year or two ago Mr. H. T. Mennell obtained at Guernsey a 

 specimen of this species in a valve oi Pecten maximus. The dried 

 sponge is of a brown colour. 



Cliona gracilis. PL VII. fig. 4. 



Spicula of three kinds, — the first pin-like, about -j\- inch long, 

 generally a little bent, stout, and inclining to fusiform, with the 

 pointed end gradually tapering ; head rounded, somewhat ellip- 

 tical, and merging imperceptibly into the shaft ; the second kind 

 is fusiform, one-third the length of the first, less stout, and 

 gradually bent in the centre ; it is minutely spined, and has the 

 extremities sharply pointed : the third form is about ttW 2?^^^* 

 long, and is usually zigzagged so as to form four or five angles ; 

 it is most minutely spined, and has the extremities rounded and 

 recurved. 



When dry, the sponge is of a yellowish-brown colour. 



Cliona Howsei, PI. VII. fig. 5. 



Spicula of three kinds, — the first pin-like, about y—- inch long, 

 very delicate, generally straight, with the head broadly ovate, 

 short, well-marked, terminal, and having the narrow end at the 

 extremity, and sometimes a little prolonged : the second form is 

 abundant and generally somewhat longer than the first ; it is 

 equally slender, mostly slightly bent, and gradually diminishes to 



