PORIFERA 



27 



masses of a slate-grey one, sometimes as large as a quartern 

 loaf, with the osculae arranged in lines on its surface this 

 is Pachymatisma Johnstonia ; pink or purple ramifying 

 branches of Isodictya Ingalii ; branches of Chalina occulata, 

 with the osculae arranged along the sides of the branches ; 

 perhaps the Tangerine orange, resembling one, Tethya 

 lyncurium. If within some dark recess a black India- 

 rubber-like to both look and touch one is seen, it is a 

 prize it is Dercitus niger. If harsh, needle -clad, rubblv 



From Calcisponges From Silicisponges 



Fig. 12. Some typical forms of Spicules 



branches, about an inch in height, and plentifully coated 

 with oozy mud, are perceived, this is Raspalia also a 

 prize. 



All these may look to the novice very uninviting and 

 uninteresting things compared to the pretty shells and the 

 gay sea-weeds strewn around, but I must here tell him that 

 the microscopic preparations of these, which he will soon 

 know how to make, are some of the most exquisitely 

 beautiful, as well as interesting, things of which the mind 

 can conceive. 



