October 3, 1884.] 



SCIENCE. 



335 



was aware of the apparent exceptions signalized by 

 Mr. Dall, and could add extinct forms referred to the 

 Pteriidae or Aviculidae, as well as the Muelleriidae 

 retained among the Dimyaria. The Monomyaria 

 seemed to me, however, to be a natural ' genetic ' 

 group, and the Muelleriidae were bimusculose in 

 youth, and their monomyarian characteristics in the 

 adult appeared to be a peculiar teleological adaptation. 

 I am still disposed to believe that the Monomyaria con- 

 stitute a natural group, although Mr. Dall has good 

 reasons for thinking that, "in fact, there does not at 

 present seem to be any good basis for ordinal divis- 

 ions in the Lipocephala." What Mr. Dall designates 

 as ' the remarkable characters of the group of Met- 

 arrhiptae ' seemed to me to furnish as good a basis 

 for an ' order ' as any of those that have been used for 

 that purpose: consequently I gave the name as an 

 ordinal designation in 1871. 



But the question whether certain groups are of 

 ordinal or minor value is of less moment than the 

 natural subdivision of the class. If the myological 

 peculiarities are not the best criteria, what are? 



A view that has had some currency, that the Mo- 

 nomyaria are inferior forms of Acephala, is negatived 

 by both embryological and paleontological evidence. 

 The testimony of both is conclusive that the Mono- 

 myaria are derivatives from Dimyaria. 



is it certain that the shell of the Polyplacophora 

 (Chitons) is the exact homologue of the shells of the 

 typical Gastropods ? I am acquainted with what has 

 been published of the embryology of the group, but 

 am left in doubt both as to facts and interpretations. 

 At any rate, it is certain that the old views of a close 

 relation between the Polyplacophora and the doco- 

 glossate Gastropoda had very little morphological 

 basis. 



My gratitude for the excellent article of Professor 

 Lankester impels me to cordially indorse the encomi- 

 ums of Mr. Dall, while I concur with the critic as to 

 the family arrangement. 



Professor Lankester has sometimes been misled, 

 too, by not remembering that the same objects may 

 be called by different names : for instance, he has 

 referred to the 'Rachiglossa (1.1.1, or 1),' a gastro- 

 pod named ' Pyrula, Lam. (fig. 38),' but the figure 

 represents a type belonging to the ' Tenioglossa 

 (3. 1. 3),' and repeated thereunder as one of the 

 ' family 4, Doliidse,' under the name ' Ficula.'' As 

 my eyes light on neighboring names, I may add 

 that the ' Pediculariidae ' and ' Ovulum ' do not 

 fulfil the conditions of the ' Siphonochlamyda,' — 

 * shell always spiral:' they do not have true spires. 

 Professor Lankester has been deceived by false 

 guides. Such lapses are, however, of a kind inevi- 

 table in a general work; for it is impossible for one 

 man to verify every statement. Theo. Gill. 



A fasting pig. 



Ix a recent flood (June 26) that visited this neigh- 

 borhood, Mr. John Aughenbaugh of West Manchester 

 township had five hogs carried away by the water. 

 On Aug. 7 one of them was found under a large 

 heap of driftwood about a mile from the home of 

 Mr. Aughenbaugh. Tbe animal had been securely 

 imprisoned by the timber, and had not eaten any 

 thing for forty-two days. Although very consid- 

 erably emaciated when released from its prison, it 

 appeared to have no trouble in emptying a crock of 

 thick milk that was offered it. It has since been 

 doing well, and no doubt will soon recover all it lost 

 in flesh. E. F. S. 



York, Penn. 



A WIDER USE FOR THE LIBRARIES OF 

 SCIENTIFIC SOCIETIES. 



To those who are obliged to use the libraries 

 of our smaller colleges, it is often a source of 

 vexation to find that the books one is referred 

 to are wanting. The resources of the colleges 

 are limited, and the amount of money which can 

 be expended for the purchase of new books 

 small, and that small amount often devoted, 

 according to the wishes of the donor, to the 

 class of books least needed. A case in point 

 occurred lately, where a college professor of 

 mathematics was asked to write a short account 

 of the life of Todhunter ; and he felt obliged 

 to say that he would be glad to undertake the 

 article, but could not before he had visited the 

 libraries of either New York or Boston, which 

 he hoped to be able to do during his next 

 vacation. 



This constant lacking of just the books one 

 needs for his work is most hampering. It is 

 not the Century, or the Harper, or the latest 

 novel, or the new book of travel, which 

 cannot be had (these find their way into all the 

 odd corners), but it is the specialist's books, 

 a volume of the transactions of some learned 

 society, a scientific journal, or the modern 

 treatises on thermo-dynamics, on electricity, 

 or on biology, which are needed, and which 

 can be found only in a very few of our libraries 

 in the necessaiy profusion. 



A few such libraries have now been collected 

 by our older scientific societies and our larger 

 colleges. The books of the college libraries 

 are for a specific purpose, and find abundant 

 use at the hands of the students and professors. 

 With the societies the matter stands ciifferentry. 

 It cannot be denied that one of the original 

 objects of the establishment of these societies 

 was, that, by the publication of their own 

 ' proceedings,' they might, by exchange, gather 

 a collection of books which could not, in the 

 then comparatively poor state of the countiy, 

 be gathered in any other way, and which were 

 to be for the use of the members, and such 

 favored friends as they might designate. 



It has so happened that these societies were 

 established by the small knots of scientific 



