CORRESPONDENCE. Il7 



Spiral Vessels to Mount.— Let them be soaked in dilute nitric 

 acid, in which a few grains of nitrate of potash is dissolved, 

 picking out the vessels carefully with a needle, and well wash in 

 water. They may then be mounted at once in glycerine jelly, or 

 further prepared for mounting in balsam. J. Carpenter. 



Testacella. — This mollusc, according to Westwood, is carnivo- 

 rous, feeding on earth-worms, coming to the surface only at night. 

 Its dentition resembles the lanthincc. I am inclined to think they 

 are much more common than is supposed, but people do not 

 know where to search for them. H. E. Freeman. 



EXPLANATION OF PLATE XIL 



Fig. 1. — Entrance to the Nest of a Trap-door Spider, Cteniza Mog' 

 gridgii, with the door open. The small dots on the surface of 

 the door represent holes made by the claws of the spider in 

 holding down the door when alarmed. 



Drawn by G. H. Bryan. 



,, 2. — Aspidiotus, X 50, showing an., antennte ; m. , mouth; sp., 

 spiracles. Drawn by H. M. J. Underhill. 



,, 3. — Section of Screw Pine. 



,, 4. — Rough sketch of tree. Drawn by A. Hammond. 



,, 5. — Spinnerets of Spider, x 25. It has been attempted to give 

 a general view of the specimen, so far as could be done in so 

 small a figure, without attempting too much detail. 



Drawn by Tuffen West. 



Corrcspoubcncc, 



[The Editor does not hold himself responsible for the opinions or statements of 

 his correspondents.] 



[ To the Editor of ' ' The Journal of Microscopy and Natural Science. "] 

 Sir, — 



The statement of "B.Sc, Plymouth," on p. 56 

 of your January number, is most misleading. 



The root (so-called) of Beta is not a stem structure at all, as 

 a perusal of any modern text-book of Botany will show clearly. 

 The uppermost portion of it — i.e., the part which tapers downwards 

 to the ' shoulder ' — corresponds to the tigelhwi of the embryo, 

 this structure often forming a considerable part of the so-called 

 'root,' as_ in turnip, radish, cyclamen, etc., etc. All hehnu this 

 shoulder is root proper, and bears the well-known distinctive 

 characters of root-structure as opposed to stem-structure. 



