374 



SCIENCE. 



[N. S. Vol. VII. No. 168. 



contributions upon this phase of the subject 

 are beginning to appear. 



Lastly, it is the opinion of the writer that 

 the physiologist has not yet entered upon 

 the greatest task awaiting him, in the trans- 

 lation of the forms of activity shown by the 

 vegetal organism into a system of general 

 physiology, establishing a secure basis upon 

 which coordination of accrued results may 

 be made, a consequent better organization of 

 the forces of attack upon waiting problems, 

 and a more perfect articulation with all 

 branches of biological science secured. The 

 fact that this has not been' accomplished is 

 in part accountable for the nebulous ideas 

 concerning the scope and status of the sub- 

 ject among even the botanical contingent. 



In conclusion, it is to be said that it is 

 manifestly impossible to do more than out- 

 line the developing principles which con- 

 stitute the science of physiology, and suggest 

 a few of the great gaps which remain to be 

 filled by the efforts of future investigators. 

 Moreover, the constant broadening of the 

 biological sciences will demand a projection 

 of physiological activity to cover widely 

 diverging branches, and the interpretation 

 of forms of activity of protoplasm yet un- 

 known or but dimlj' recognized. 



[Since the paper as above was prepared 

 for the printer, Professor Loeb, in a discus- 

 sion of the fundamental problems of animal 

 physiology in this Jodenal (Vol. VII., p. 

 154, 1898), has called attention to certain 

 facts showing that the fundamental problems 

 in the two branches are in part identical and 

 in part closely parallel. His estimate of 

 the outlook, " At no time since the period 

 following the discovery of the law of con- 

 servation of energy has the outlook for 

 physiology appeared brighter than at pres- 

 ent," applies to this entire department of 

 biological science.] 



D. T. MacDougal. 

 University of Minnesota, 



Minneapolis, Minn. 



THE 3I0UTH-PABTS OF THE BHYN60TA. 



Two papers on the above subject have 

 been published within the last j'ear or two, 

 showing that there is yet a very consider- 

 able difference of opinion as to the real 

 homologies of the beak and four inclosed 

 lancets which form the Hemipterous mouth. 

 The first of the papers in point of time and 

 very much the most important is by Dr. 

 Richard Heymons, in the Ent. Nadir., 

 XXII., 11, for 1896; the second is by Dr. 

 N. Leon, Zool. Anz., XX., 73, March, 1897. 



Dr. Leon carefully describes the beak in 

 several species of aquatic Hemiptera and 

 particularly two little processes from the 

 tip of the second (third) joint, which he 

 homologizes with the labial palpi. It is to 

 be noted that both Leon and Heymons as- 

 sume it as unquestionable that the beak is 

 a modified labium. In support of his 

 thesis Dr. Leon shows that by proper ma- 

 nipulation the original paired character of 

 the beak becomes evident and he makes the 

 basal joint homologous with the submentum 

 (labial cardines); the second with the men- 

 tum (labial stipes), and the third and fourth 

 with the glossa and paraglossa. There is 

 some confusion in the descriptions and in 

 Gerris the third joint is made mentum 

 without explanation. The chief point of 

 the paper, however, is in the identification 

 of the two little lateral processes from the 

 so-called mentum as true labial palpi. 



I have seen these same processes and 

 would be inclined to consider Dr. Leon's 

 arguments sound, if I did not believe the 

 fundamental assumption that the beak is 

 labial to be incorrect. 



Dr. Heymons dismisses these processes 

 from embryological data in the conclusion 

 that 'labial palpi, consequently, are lack- 

 ing in all Ehyngota. The processes discov- 

 ered on the beak of Nepa and Belostoma are 

 not really such, but must be regarded as a 

 secondary process of the third joint of the 

 beak. 



