70 



SCIENCE. 



[N. S. A'OL. I. No. 3. 



always nearly thi'ough the entrance-point 

 of the sperm. Regarding the former point 

 there is a possible source of error in that 

 the excenti'ic egg-nucleus may wander fi-oni 

 its original position (near the polar bodies) , 

 so that the diameter passing through it no 

 longer represents the egg-axis. (This can- 

 not be determined fi-om the polar bodies, 

 since they quickly become detached from 

 the egg). Many facts indicate, however, 

 that such wandering does not occur. If it 

 does not, then the polarity of the egg is not 

 primordial but induced, and one of the most 

 fundamental characteristics of the egg is 

 thus brought into the category of epigenetic 

 phenomena. 



Professor Charles S. Minot, of the Har- 

 vard Medical School, presented a paper upon 

 The Olfactory Lobe. He showed that of 

 eleven layers of cells in the olfactory lobe 

 onlj the inner two layers belong to the cere- 

 bral cortex proper, proving that the olfac- 

 tory lobe is a ganglion structure belonging to 

 the sensory ganglion series with certain great 

 secondary modifications. This is further 

 supported by the fact that' the lobe primar- 

 ily connects with the brain at a point topo- 

 graphically similar with a point midway be- 

 tM^een the ' dorsal zone ' and the ' ventral 

 zone ' of His. In a second paper Professor 

 Minot pointed out as a Fundamental Difference 

 Betiveen Animals and Plants, of value princi- 

 pally in teaching, that while animals feed 

 typically upon solids, plants always procure 

 their food in a gaseous or hquid form. This 

 paper was discussed by Dr. Locy, Dr. 

 Humphries and several other botanists and 

 zoologists present, the point being raised 

 that plants manufacture their own food and 

 that when plant assimilation really begins 

 it is practically analgous to that of animals, 

 as it consists in the taking up of solid par- 

 ticles. 



Dr. Arnold Graf, of Columbia, presented 

 the next paper upon The Origin of the Pig- 

 ment and the Causes of the Presence of Patterns 



in Leeches. The pigment originates in the 

 excretophores. These are wandering cells 

 which pick up excretory substances fi-om 

 the walls of the capillaries ; one part of the 

 cells wanders to the funnels of the nephri- 

 dium and thus delivers their contents into 

 the nephridium, wliile another part of the 

 excretophores wanders under the skin 

 emerging along the lines of least resistance, 

 which lie between the muscle bundles. 

 The color patterns of the leeches vary, 

 therefore, according to the arrangement of 

 the musculature. In Nephelis the longitud- 

 inal musculature is developed most strongly 

 and consequently the pattern consists in 

 longitudinal stripes. Clepsine has as a con- 

 sequence of its parasitical mode of life a 

 strongly developed dorso-ventral muscula- 

 ture and therefore the pattern consists in 

 spots, the loug-itudinal sti'ipes ha^dug been 

 interrujjted and broken up by the trans- 

 verse and oblique muscle bundles. The 

 bearing of these facts is very important. 

 The color pattern of the leeches is not in 

 itself adaptive; it is entirely incidental and 

 secondary to the musculature which is es- 

 sentially adaptive. A change in the mus- 

 culature Avould result in a change in the 

 superficial color pattern. This shows how 

 a very striking superficial character maj'' 

 originate without any adaptive significance 

 and as a secondary inheritance. 



The following paper bj' Professor H. T. 

 Fernald, of Central College of Pennsylvania, 

 was entitled Homoplasy as a Factor in Mor- 

 phology. A review of zoological Hterature 

 in the past ten years shows that in every 

 group of animals beginning wdth the sponges 

 and extending iip to the highest vertebrates 

 the phenomenon of parallel or homoplastic 

 development is becoming increasinglj' ap- 

 parent. Numbers of cases were cited fi-om 

 all classes of animals showing that identical 

 sti'uctures, produced independentlj' in differ- 

 ent phyla, are extremely numerous.. The 

 paper was discussed by Professors Hyatt, 



