April 28, 189;,.] 



SCIENCE. 



229 



initted to the fangs of rattlesnakes, and other large viperine ser- 

 pents are very much more quickly digested, not only by snakes, 

 but by toads and other carnivorous reptiles, and even mammalia, 

 than pieces of meat or animals of corresponding species which 

 have not been so treated. 



There can be very little doubt that this morbific fluid, this 

 venom, is a product of a recent evolution. The venom gland, 

 although large, is distinctly one of the salivary glands iu struc- 

 ture, one of the racemose group, very little altered in appear- 

 ance from that which secretes the ordinary saliva, the venom 

 being in fact an abundant saliva, and containing some toxic ele- 

 ment the nature of which has not yet been distinctly ascertained, 

 in addition to the ordinary salivary products. There is probably 

 no other instance in nature of the enormous disproportion of 

 change of function when compared with change of structure 

 as obtains in the venomous fluid of the gland of a poison- 

 bearing snake, unless indeed it be the function of the brain of 

 man when compared with that of animals almost equal to him 

 in complexity of cerebral structure. 



There remains, however, a third group of serpents, gifted with 

 the power of killing their prey before deglutition. These, which 

 number possibly 400 or 500 species (the number not being accur- 

 ately ascertained owing to absence of observation of living spec- 

 imens), may be termed the Constrictive Group ; and although 

 no such physical distinction can be drawn between these and 

 the ordinary or Colubrine snakes on structural grounds, as is at 

 once apparent between the latter and the venomous group, yet 

 the process of feeding is so entirely different, as to suggest the 

 feasibility of establishing such a difference, by careful dissection. 

 With these snakes the prey is slain at the moment of the seizui'e, 

 by constriction, by being wrapped within tbe folds of the body 

 and crushed to death ; and this process is so remarkable in its 

 vigor and in its rapidity, that it is impossible to imagine the 

 creatures destitute of specially developed, if not specially sup- 

 plied, muscles for this purpose. 



This group includes not only the great Anaconda of tropical 

 America, the very much smaller Boas of that region, as well as 

 the Tree Boas, and the Pythonoid snakes of Africa and the East 

 Indies, but very many smaller species as well. The black snake 

 of North America is indeed distinctively named Coluber Con- 

 strictor ; but there are very many other species manifesting 

 this peculiarity which have as yet obtained no such distintive re- 

 cognition, such as the Blue Racer of the States, the Saw-marked 

 snake of South America, and the largest of the European ser- 

 pents, the beautiful four-rayedElaphisof Italy and Greece, which 

 -occasionally attains a length of six feet, and is capable of swal- 

 lowing a large rat. 



It is just possible that this power of constriction may have 

 been acquired recently, like the venom of the poison-bearing 

 snakes. Unfortunately, paleontology affords no evidence upon 

 this point. "We know very little of the evolution of the Ophidia. 

 Fossils are very scarce; and although some of them, such as the 

 noted specimen from the London Clay, suggest serpents of 

 large size, and therefore presumably constrictors, we know noth- 

 ing beyond what is suggested by mere inference as to whether 

 they were gifted with venom, or had this property of constrict- 

 ing their prey before swallowing. 



If we examine the lateral and intercostal muscles of one of the 

 large Pythonoid snakes, we shall find that although these are 

 very highly developed, and have indeed in certain instancessmall 

 tendenous slips attaching them to the ribs, which are not found 

 in smaller species, they are precisely analogous to the ordinary 

 intercostal muscles which obtain through the whole of this 

 family. 



In certain species, such as the Milk snakes of the Northern 

 states, and the Mandarin snake of China, we may occasionally 

 see, when they are dealing with prey rather too strong for them, 

 a sort of attempt made at constriction, a rapid coiling and un- 

 coiling of the body, as though to confuse the animal struggling 

 within the grasp of the jaws and teeth. And it is perhaps not 

 wholly unjustifiable to imagine Ihat this power of constriction 

 may originally have been acquired in this way ; that serpents 

 which had previously fed, as our ordinary Colubrine snakes do, 



upon;frogs, lizards, and soft-bodied animals which they could kill 

 by pressure of the jaws alone,found themselves.for some reason or 

 other, reduced to catching the smaller mammalia, mice, moles, 

 etc. , and that in their endeavors to get these within the cavity 

 of the mouth, they found it necessary to bring the body into play 

 to effect the purpose which had hitherto been accomplished by 

 the jaws alone. One may, however, express the hope that when 

 larger materials are at hand for examination, in the shape of 

 the grander Pythonoid snakes, and most especially of the great 

 Water Boa, the Anaconda of Central America, that some more 

 definite information on this point will be gleaned. 



NOTES AND NEWS. 



At a recent meeting of the Canadian Institute, Mr. Andrew 

 Elvins asked permission to add a sentence or two to his paper on 

 the satellites of Jupiter, read at a former meeting. He said: 

 "The period of each satellite as we pass outward from the planet 

 is about double that of the one next inside itself, except in the 

 case of Satellite I. Half its period would be about 21 hours, but 

 there is no satellite having that period. Half of this 21-hour 

 period is just where Professor Barnard's new satellite exists. Its 

 period is between 11 and 12 hours. I therefore think that an 

 undiscovered sixth satellite exists at 166,000 miles from Jupiter's 

 centre, with a period of 21 hours." 



— The faculty of the Museum of Comparative Zoology, Cam- 

 bridge, Mass., will receive applications from candidates desiring 

 to occupy the table at the Naples Zoological Station, which has 

 been placed at its disposal from Oct. 1, 1893. The applicant must 

 be (or have been recently) a student or instructor at some Ameri- 

 can university, preferably a person who has taken the degree of 

 Ph.D. or S.D. ; he must have published some creditable original 

 investigation, and should be recommended as an able investigator 

 by the professor under whom he has studied. Applicants will 

 please forward to Professor Alexander Agassiz, Director of the 

 Museum, before May 10, their recommendations and a statement 

 of their qualifications and of the subject to which they hope to 

 devote themselves. In order that the faculty may make the 

 most satisfactory disposition of the table during the whole year, 

 the applicants are requested to state the length of time they desire 

 to remain at Naples, and also the earliest and latest dates within 

 which they can avail themselves of the appointment. The fac- 

 ulty will, at its meeting in May, nominate to the Corporation of 

 Harvard College for approval the incumbent or incumbents for 

 the year 1893-94. 



— The papers entered to be read at the April meeting of the 

 National Academy of Sciences, are as follows: On the System- 

 atic Relations of the Ophidia, E. D. Cope ; Biographical Memoir 

 of General Montgomery C. Meigs, H. L. Abbott ; On the Nature 

 of Certain Solutions, and on a New Means of Investigating Them, 

 M. C. Lea; The Relations of Allied Branches of Biological Re- 

 search to the Study of the Development of the Individual, and 

 the Evolution of Groups, The Endosiphonoidea (Endoceras, etc.) 

 Considered as a New Order of the Cephalopods, A New Type of 

 Fossil Cophalopods, Results of Recent Researches upon Fossil 

 Cephalopods of the Carboniferous, A. Hyatt ; Biographical Me- 

 moir of Julius Erasmas Hilgard, E. W. Hilgard; Monograph of 

 the Bombycine Moths of America, North of Mexico; Part I. — No- 

 todontidse, A. S. Packard; Intermediary Orbits, G. W. Hill; The 

 Relations between the Statistics of Immigration and the Census 

 Returns of the Foreign-born Population of the United States, 

 Statistical Data for the Study of the Assimilation of Races and 

 Nationalities in the United States, Richmond Mayo-Smith; Tele- 

 graphic Gravity Determinations, Comparison of Latitude 

 Determinations at Waikiki, T. C. Mendenhall; A One- 

 volt Standard Cell, H. S. Carhart (introduced by T. C. 

 Mendenhall); Fundamental Standards of Length and Mass, T. 

 C. Mendenhall; Peptonization in Gastric Digestion, R. H. Crit- 

 tenden ; Helen Kellar, Alexander Graham Bell; On a Potential- 

 ity of Internal Work in the Wind,OnaBolograph of the Infra-red 

 Solar Spectrum, S. P. Langley; The Classification of the Gastro- 

 podous Mollusks, Theo. Gill. Presentation of the Draper Medal 

 to Professor H. C. Vogel. 



