Recent Proceedings of Societies. 



Academy of natural sciences, Philadelphia. 

 j une g. — Dr. Benjamin Sharp reported that, while 

 recently studying the eyes of serpents, he had ob- 

 served that in the poisonous snakes the pupils were 

 elliptical, while in the harmless species they were 

 circular. The only exception to the rule, that he 

 was aware of, was in the case of the Elapidae, a 

 family of poisonous coluberine snakes in which the 

 pupil is circular ; but in these the poison fangs are 

 fixed, and do not move as those of other venomous 

 forms. Professor Sharp also spoke of the mechan- 

 ism by means of which the eye accommodates itself 

 to distance. It is well known that this is effected by 

 the contraction of the ciliary muscle, drawing on the 

 point of attachment of the capsular ligament of the 

 lens, the optical axis of which is widened as soon 

 as the tension is released. As far as the speaker 

 knew, the mechanism of the lenticular expansion 

 had not been described. He had found that press- 

 ure on the lens in its earlier stage of development 

 compressed the elongated cells of the posterior wall 

 in their long axis. When the pressure is removed, 

 they simply straighten out, thus accounting for the 

 fact that the anterior face of the lens is the only por- 

 tion that moves in the act of accommodation to dis- 

 tance. Although the adult lens is composed of 

 concentric layers, the embryonic impression still re- 

 mains. D r . Foote gave an interesting account of 



his recent expedition to Mexico in search of minerals. 

 He described particularly the mines of Queretaro, 

 which have long been noted for the quantity and 

 quality of the precious stones yielded by them. The 

 locality was discovered in 1850, but little was done 

 to develop it until twenty years later, when a large 

 quantity of specimens were taken out. Since then 

 eighteen or twenty mines have been opened, al- 

 though the principal one, the Esperanza, is not at 

 present worked. The district is about twenty-five 

 leagues long by six leagues wide. Opal of varying 

 quantity has been found over all this area ; much of 

 it, in the speaker's opinion, being quite equal to the 

 best Hungarian opal. The workmen are able to 

 predict from the character of the rock the kind of 

 mineral which will be found embedded ; the hard, 

 firm stone yielding fire-opal, while the soft, gray 

 matrix contairs the precious and harlequin opal. At 

 present none of the mines are producing opal suit- 

 able for cutting into gems. The tourist is likely to 

 be deceived in the quality of the mineral offered to 

 him. because, both at the mines and in the city of 

 Mexico, the specimens are kept in little saucers of 

 oil, not so much, the speaker believed, to preserve 

 them from cracking, as to enhance their brilliancy. 

 The Mexican lapidaries were much more skilful than 

 ours in cutting the opal without producing cracks. 

 The fire, precious, and harlequin opals were de- 

 scribed, and specimens from the several localities 



alluded to were exhibited. The president, Dr. 



Leidy. remarked, that, with the exception of the 

 fire opals, he had never seen a Mexican opal which 

 would stand the test of a few years without crack- 

 ing. For this reason, in his opinion, gems cut from 

 the Mexican mineral were worthless, although the 

 color is frequently as fine as that of the best Hungarian 

 opal. The Honduras specimens were not open to 

 the same objection. He believed it was of benefit 



to the Mexican opals to keep them in oil, as they 



would probably thus be preserved from cracking. 



Professor Heilprin called attention to a remarkable 

 case of vitality among certain members of the fauna 

 of the New Jersey coast. Specimens of Nassa 

 obsoleta and Littorina saxatilis, two marine snails, 

 collected by Miss Emma Walter at Atlantic City just 

 one year ago, were stated to be still alive, although 

 subjected for several months to the abnormal tem- 

 perature occasioned by proximity to a heated wall 

 surface. This was, perhaps, the most extraordinary 

 instance of vitality known among the marine Mol- 

 lusca, although among the terrestrial and fresh- 

 water forms, especially among those which undergo 

 a partial hibernation, long periods of survival have 

 been noted. Instances were cited by the speaker 



and Dr. Leidy. Dr. Harrison Allen alluded to 



certain peculiarities in the muscles of mammals, and 

 took exception to the term ' fuse ' as applied in some 

 cases to contiguous muscles or to separated layers of 

 the same sheet of fibres. He believed that in no 

 case could muscles properly be said to be fused. In 

 certain cases, as in the biceps of the cat, a portion 

 simply overgrows the space originally allotted to it, 

 and takes advantage of an adventitious surface of 

 insertion. Others, as the pectoralis in man, are 

 composed of a single sheet folded on itself. The 

 quadriceps extensor of the skunk he had found to be 



a muscle of the latter sort. Dr. Charles S. Dol- 



ley presented for publication and read an interesting 

 paper on the histology of Salpa, a genus of tunicates. 



Calendar of Societies. 



Connecticut academy of arts and sciences. 



June 16. — C. S. Hastings, A new spectrometer ; 

 A. E. Verrill, Successful artificial propagation of 

 marine fishes and lobsters by a new method. 



Publications received at Editor's Office, June 7-12. 



Afrika, speziaf-karte von. Scale 1:4000000. Lief, v.: West- 

 Sudan. Seengebiet. Gotha, Perthes, 18S6. 2 maps. f°. (New 

 York, Christern. 80 cents.) 



Agassiz, Louis, proceedings at Cornell university, in memory 

 of, and in honor of Hiram Sibley. Ithaca, Trus. Cornell univ. y 



1885. 38 p 8°. 



Bary, M. de. Lecons sur les bacteries. Tr. by M. Wasserzug. 

 Paris, Masson, 1886/ 324 p., illustr. 8°. (New York, Christern, 

 $1.65.) 



Gavoy, E. L'encephale structure et description iconographique 

 du cerveau, du cervelet et du bulbe. Livr. 1. Paris, Ba/lliere, 



1886. 8-I-24 p., 12 pi. 4 . (New York, Christern, $6.65.) 

 Huergo, L. A. Examen de la propuesta y proyecto del 



puerto del Sr. D. Eduardo Madero. Part i. and ii. Buenos 

 Aires, Bzedma, 1886. 152+195 p., 2 maps. 8°. 



Novicow, J. La politique internationale. Paris, Bailliere, 

 1886. 28-I-393 p., map. 8°. (New York, Christern, £2.35.) 



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