THE society's NOTE-BOOKS. 247 



In answer to above query, we have here (Portugal) very com- 

 monly the caterpillar of a moth, Cncthocampa pityocampa, the 

 hairs of which are said to produce irritation. It makes its 

 nest in the pine trees, " Pinus viaritinia,'^ in a colony, closely 

 packed ; they are dormant during the day, sallying out at night to 

 feed on the trees. In one case I am told that a man's shirt was 

 spread out to dry on the ground under one of these trees. After 

 putting it on the irritation drove him nearly wild, and it was found 

 that there was a nest of these caterpillars just above where the 

 shirt had been laid. It is supposed that the hairs from the cast- 

 off skins of these caterpillars fell on it. 



I have examined these hairs under the microscope, and found 

 nothing very remarkable in them, except that they seemed very 

 sharp and needle-like, but will examine them again, as also those 

 of an allied species which feed on the leaves of the Cistus, or 

 Rock Rose, and report further. 



W. C. Tait. 



Plant Crystals. — I cannot agree v\'ith those who suggest that 

 the polariscope should not be used in the examination of these 

 objects. According to my old friend and tutor, Mr. Rainey, a 

 microscopist should never be satisfied tliat he knows all about an 

 object until he has examined it by ail the means at his disposal ; 

 and certainly one can least of all afford to dispense with the aid of 

 the polariscope, which often reveals to the observer differences of 

 structure before unexpected and often impossible to ascertain in 

 any other way. 



J. W. Measures. 



Bird's Head Processes. — In September last, while examining 

 the bird's head processes on Cellularia received from 

 Mr. Bokon, a minute Crustacean was seized by the leg and 

 detained by the beak-looking appendage for three days, after 

 which I was unable to make any further observations. This 

 would seem to embody Mr. Goss's conjectures. 



J. W. F. DUNLOP. 



Crystals of Santonine. — I believe that the wheel or disc-like 

 form of the crystals of Santonine is due to the specimen having 

 first been ev^aporated to an " amorphous film," and then allowed 

 to absorb its " water of crystallisation " from the air. Many 

 crystals, such as copper sulphate, baric chloride, salicine, etc., do 

 this; the form of their crystals is then very different from the 

 normal shape, but I believe that the aui:;les of both forms of 

 crystals will be found to be exactly alike. 



H. M. J. Underhill. 



