The most particular pains should be taken with all the "bearded" species, 

 and no chiton with "whiskers," even the smallest, should be dried and 

 cleaned unless you are quite certain that it is some common and well- 

 known form of which you have plenty to spare; rather it should be killed 

 carefully in the expanded condition, having bound it so as not to injure 

 any specialized setae which may be borne by the girdle, and then put up 

 in alcohol until it can be studied by some competent student. Cotton, 

 owing to the inevitable entanglement of its fibers in the bristles, is not a 

 satisfactory packing material for specimens of this type; cheesecloth or some 

 light, non-absorbent paper is better for the purpose. Many of our bearded 

 species are so poorly understood that even an inexperienced collector has 

 a chance of picking up something which promises, at least potentially, to 

 effect some real addition to knowledge. It will then be realized that it is 

 far better to make the slight additional effort necessary to put up a rela- 

 tively small collection in proper shape, whether it is to be kept in alcohol 

 or dry, than to take so large a mass of material that none of it can be 

 handled decently and a mass of misshapen, dirty, ill-smelling cadavers, the 

 bane of whomsoever is so unfortunate as to have to work them up, is the 

 oiily result. Such material is costly to the time, patience, and efficiency of 

 the student infinitely in excess of the little trouble the added care in the 

 field would have entailed. A chiton collection which is in the main a 

 slovenly mess possesses no attractiveness and little value. 



Allusion has already been made to the rare occurrence of individuals 

 possessing either more or less than the normal eight valves. These are of 

 interest to the teratologist or pathologist rather than to the systematist, but 

 the curious and uncommon of whatever nature always seems to possess 

 intrinsic appeal to the collector, and as these specimens are surprisingly 

 easy for most people to overlook unless trouble is taken actually to count 

 each set of valves, it becomes a source of considerable entertainment to 

 keep a weather eye out for them, remembering that they are easier to 

 detect when working over one's catch in the laboratory or at home than 

 they are amid the swirling rush of the rocky shore. Specimens with super- 

 numerary valves appear to be by all odds the rarest; a very few with 9 

 valves (I, myself, have seen precisely one), and none, so far as I can learn, 

 with more than 9 are recorded in the literature. Those with valve defi- 

 ciencies on the other hand are of very much more frequent occurrence. 

 Most large collections can boast a few specimens with 7 valves, occasionally 

 one with 6, and, more rarely, one with 5. The most common type of appar- 

 ent deficiency is not due to any actual lack of a segment, but is purely 

 superficial, having been caused by some early mechanical injury as a result 

 of which two or more valves have undergone more or less complete fusion. 

 Careful examination of the structure of the valves, particularly of the 

 articulamentum, will u' ually reveal the presence of parts at least of all 8 

 of them, and pretty well indicate what must have taken place. Outright 

 deletion of valves is a much rarer phenomenon, and when this has occurred 

 it is difTicult or even impossible to determine which valve is the missing one. 



(48) 



