Oct. 1 6, 1879J 



NATURE 



595 



These sustentor ridges are homologous with the limb of the anal 



To-legs and the exposed edge with the posterior border of said 



.".lb. They vary mnch in form, and may be more or less 



bsolete. 



Fom-thly, between them is what may be called the rectal piece, 



: insisting of a piece more or less well marked and elevated, 



;jecially around the closed rectum. 



It is principally by the leverage obtained by the hooking of 



the sustainers in the retaining membrane, which acts as a swing 



ing fulcrum, that the chrysalis is prevented from falling after the 



lemaster is withdrawn from the larval skin. It is also princi- 



ciUy by this ^ame means that it is enabled to reach the silk with 



iC cremastral hook-pad. Yet the rectal ligament plays a most 



..portant part, and in some species a more important part 



.en, in my estimation, than the membrane itself. The tracheal 



;_;aments which, from a study of specimens plunged in alcohol 



hen the larval .'•kin was about half shed, I was at first 



dined to believe important auxiliaries, are, I am now 



uisfied, of very little if any Eer\'ice in most cases. The rectal 



_;ament is a constant physiological factor, : nd its importance 



iimot be ascertained by attempts to sever the membrane at 



'..•i critical moment, because in such attempts the ligament is 



ore or less drawn out beyond the power of the sphincter 



uscles in the chrysalis to control it. 



Dissected immediately after suspension, the sub-joint of the 

 larva will be found to be lying, esj ecially between the legs 

 and around the rectum, in an abundance of translucent, mcm- 

 branou.s material. An hour or more after suspension the end of 

 the forming chrysalis begins to separate from the larval skin, 

 except at the tip of the cremaster. Gradually the skin of the 

 legs and of the w hole sub-joint stretches, and with the stretching 

 the cremaster elongates, the rectal piece recedes more and more 

 from the larval rectum, and the sustentor ridges diverge more 

 and more from the cremaster, carrying with them, on the 

 sustainers, a part of the soft membrane. If a larva be 

 carefully dissected at this stage, the forming membrane may 

 be raised with the point of a needle, and stretched so as 

 to show its connection with the rectal ligament ; or it may be 

 lifted entirely from the retainers, when, by its elasticity, 

 it contracts, and becomes more cr less fully absorbed in 

 the rectal ligament. It is at this stage that the strength of 

 the latter may be fully tested, and if the chrysalis, flayed from 

 •'le larval skin, and freed from the retaining membrane, be 

 .isped in the neighbourhood of the rectum, so as to supply the 

 itural holding power of the sphincter muscles, the rectal liga- 

 lent will sustain, as I have abundantly proved, at least ten or 

 • ■■. elve tmies the weight of the chrysalis ; while it will sup- 

 rt, if held by the larval skin, several times the weight 

 the chrysalis before separating therefrom. In brief, the 

 laining membrane is that part of the inner larval skin 

 ; rounding the pro-legs drawn down by the sustainers, and 

 ■ays intimately connected with and forming but a branch 

 the rectal ligament. When extended from its attaclmients, 

 when the clirysalis rises to the silk, this membrane dries, and 

 1:1 the cast-off larval skin retains more or less perfectly the 

 stretched form. If the corium of the larva be thick and strong, 

 a^ in Vanessa, the dried membrane will be broad, with two in- 

 dentations where it was held by the retainers ; if the corium be 

 more delicate, as in Dannis, Paphia, or Apatura, the dried 

 membrane will be more forked, showing how the retainers have 

 ncted n|X)n its elasticity. In every case, h nvever, it shows, 

 iler the microscope, the longitudinal folds and creases incident 

 the stretching, and, compared to the rectal lif^ament proijer. 

 It seems to lose importance as it is less needed ; for the succincti 

 will generally attach when it is severed or loosened from the 

 retainers, while in Apatura (at least as exemi.Iified in the North 

 American species), which combines the peculiarities of both the 

 uccincti a.nA suspensi,^ it does not become s|)eeiali-ed, and the 

 chrj-salis seems to rely almost entirely on the rectal ligament, 

 assi.sted by the partial holding of the delicti te 1 irv.-il skin, not 

 only between what is left of the sustainers and the ventral poste- 

 rior margin of the twelfth joint, but between ihc- ventral sutures 

 of this la.stand the precefling joint. And hire I w..uld remark, 

 in conclusion, that the ventral borders of t.vo or three of the 

 i ints preceding the subjoint arc, in most dirysalids which I 

 ive studied, so hardened that the larval c rium is actually 



I'hc hrva of A^atur,, attaches horiionlalljr, maki: g the front pair of 

 '. .minal pri-legs answer the purpose of the'ginh ; ut in the shedding of 



kin thi.s atuchmcnt is severed, and the forminx chr,>ali» assumes the 

 l>endicular position, and in the withdrawal and iituchmcnt of the crc- 

 ■ler It acts as the true siisprnii. 



grasped between them and the deep sutures made in contracting. 

 In some instances (especially in some species of Papilio) the 

 posterior border of the twelfth joint is produced into a medial 

 transverse ridge fully as prominent as that formed by the sus- 

 tainers, which here are flattened and coalesce ; so that the 

 sutures of some of the terminal joints in the chrysalis do sub- 

 serve the purpose ascribed to them by Reaumur, but in a some- 

 what different way. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 

 The Oxford University Gazette of October 10 contains coun- 

 sel's opinion; on the proposed faculty of Natural Science at 

 Oxford. It has been iroposed that the University should, by 

 statute, establi-h a new faculty, under the name of "The 

 Faculty of Natural Science," should grant degrees of Bachelor 

 and Master in that faculty, and should give to Masters of 

 Natural Science all the rights and privileges which are now 

 enjoyed by Masters of Arts, so making them Members of Con- 

 vocation (the governing body of the University), and enabling 

 them to vote for the members returned to Parliament by the 

 University. Mr. Horace Davey is of opinion that the University 

 may create a new faculty in science, or (which comes to the same 

 thing) may sever one of the sciences or philosophies formerly 

 comprised in the Faculty of Arts, and may make it into a new 

 faculty, and grant degrees therein. Such a severance was 

 anciently made in the case of grammar, rhetoric, and music. 

 But Mr. Davey believes that the University has no power to 

 confer upon graduates in a new natural science faculty the rights 

 which now belong to Masters of Arts, and the degree of Bachelor 

 or Master of Natural Science would not make the holder a 

 Member of Convocation. This difficulty Mr. Davey suggests, 

 might be avoided by the University conferring the degree of 

 Master of Arts on any person obtaining the corresponding degree 

 in the new faculty. 



The new chemical laboratories at the Oxford University Mu- 

 seum will be opened for students this term. The chemical 

 department has now for many terms been overcrowded, and the 

 new buildings will not only afford ample space for beginners and 

 pass-men getting up their "simple salts," but contain rooms set 

 apart for special work and fitted with the best appliances under 

 the careful superintendence of Mr. W. W. Fisher, Aldrichean 

 Demonstrator. 



The new chemical laboratory at Balliol College will be opened 

 this term under the superintendence of Mr. H. B. Dixon. Balliol 

 and Trinity Colleges have combined to equip and maintain this 

 laboratory, and a physical lecture room for the use of their own 

 students. 



At the University Museum Prof. Odling will lecture, this 

 term, on Organic Chemistry ; Mr. Fisher will lecture on Ele- 

 mentary Organic, and Mr. Donkin on Elementary Inorganic, 

 Chemistry. Frof. Clifton will lecture on Elementary Electricity, 

 and Prof. Story-Mask elyne on the Use of the Goniometer. 

 Prof. Prestwich gives a course on two afternoons a week, on the 

 Pateozoic Kocks, at the Museum, and Prof. Lawson will lecture 

 on Vegetable Histology, at the Botanic Garden. Rev. C. 

 Pritchard, Savilian Professor of Astronomy, will give practical 

 instruction at the University Observatory, on fine evenings 

 during the term ; he will also continue giving public lectures on 

 the history of astronomy. Dr. Rolleston will lecture 1 n Circu- 

 lation and Respiration, and practical instruction in anatomy and 

 physiology will be carried on in the laboratory, under the super- 

 intendence of Mr. Robertson, Mr. Jackson, and Mr. Poiilton. 

 Mr. Barclay Thomp on will lecture on the Anatomy of the 

 Amphibia, at the Museum. At Christchurch Mr. Vernon Har- 

 court will give a course of lectures on the Elements of Chen'stry, 

 and Mr. R. E. Baynes will give a course on Mechanics. 



At Magdalen College Laboratory Dr. Pike will lecture on 

 Chemistry, and Mr. Yule' and Mr. Chapman on Biology. 



Exeter College has lost the valuable services of Prof. 

 T.anke-ter. Mr. Lewis Morgan, formerly house surgeon at the 

 Radclilfe Infirmary, will carry on instruction in the biological 

 laboratory of the College. 



In the month of November there will be an election at Balliol 

 College to a scholarship on the foundation of Miss Hannah 

 Brakenbury, " For the Encouragement of the Study of Natural 

 Science," worth 80/. a year (55/. and tuition free), tenable during 

 residence for four years. There is no limit of age, but members 

 of the University must not have exceeded eight terms from 



