62 



SCIENCE. 



[YOL. I., Xo. 3. 



calcic carbonate deposited to form the spat 

 sliell are prismatic and of a wholly different 

 microscopic appearance from that of the fry. 

 The facts presented above prove bej'ond a 

 donbt, that it is the mantle border of the fry 

 which is the effective agent in achieving firm 

 fixation, whatever may be the importance of a 

 temporary or larval byssus. 



This was an interesting and important point 

 to determine, on account of its practical rela- 

 tion to the artificial rearing of the American 

 oyster (Ostraea virginica) . But with the fore- 

 going comnarativeh' meagre results we may 

 say, that our success in the artificial culture 

 has ended ; and, were it not for the highly 

 encouraging recent reports from France, our 

 efforts might have rested here. The stimulus 

 which has provoked the investigations recently 

 undertaken abroad was, however, probably 

 Dr. W. K. Brooks's success with the Ameri- 

 can oyster in 1879, and his demonstration of 

 its unisexuality. 



The remarkable success of M. Bouchon- 

 Brandely in rearing spat from the artificially 

 fertilized ova of O. angulata at Verdon in 

 France, as reported in the Annals and maga- 

 zine of natural history for October, 1882, and 

 his still later reports to the minister of maiiue 

 of France in the Journal officiel de la repu- 

 blique frangaise, arc of the greatest moment as 

 applied to practical oyster-culture. M. Bran- 

 dely, after determining that O. angulata was 

 unisexual like the American sjiecies, conceived 

 the idea of rearing the spawn bj^ artificial 

 means. In order to do this, two adjoining 

 oj'ster claires, or ponds, fed by the tides were 

 arranged at Verdon ; the one acting as a reser- 

 voir from which the fresh sea-water (brackish) 

 was drawn through a tube, provided with a 

 filter consisting of a sponge at either end, into 

 the lower experimental claire. The water 

 percolated out of the latter through a bed of 

 fine sand; in this way the embryonized ova 

 placed in this pond were kept from escaping. 

 Fertilized eggs were then put into the ex- 

 perimental pond from da}' to day, while a 

 number of collectors, or tiles, were at once sub- 

 merged in the same. In somewhat more than 

 a month, success had attended his experiments ; 

 and in the course of further experiment still 

 greater success was attained when about four 

 thousand spat had been found affixed to a 

 single tile under circumstances which admit- 

 ted of no doubt as to their having been tlie 

 product of the artificially impregnated eggs 

 placed in confinement in their vicinity. It 

 was found, moreover, that the artificially fer- 

 tilized eggs had actually developed into spat 



in the closed claire a month before an}' had 

 made their appearance on the thousands of 

 tiles placed on the natural banks in the 

 Gironde. 



From a personal investigation of the an- 

 atomj' of O. angulata, we can affirm that it 

 is remarkably similar to O. virginica in the 

 structure of the generative organs, and that 

 there is no reason why as great success should 

 not attend the culture of that species by the 

 same apparently' vevy practicable means. It 

 remains to be seen, however, what proportion 

 of the artificially reared spat will reach the 

 adult condition. With an abiding faith, how- 

 ever, in the final achievement of the solution 

 of the question of the artificial culture of the 

 American oj'Ster, which will soon become a 

 positive necessity' to its culture, I think it 

 not improbable that another season's work 

 will conclude the required preliminarj' research, 

 and realize for us all the success we could 

 hope for. J. A. Rydee. 



THE MAPPEMONDE OF SEBASTIAN 

 CABOT. 



The library of Harvard College, in Gore 

 Hall, has recently been enriched with a pho- 

 tographic facsimile of tire large map of the 

 world in the national library in Paris, known 

 as the map of Sebastian Cabot. This inter- 

 esting memorial was discovered in Germany 

 about the j'ear 1844, in the house of a Bava- 

 rian curate, and, through the good offices of 

 M. de Martins, was in that year purchased 

 for the Paris library. It is a large elliptical 

 mappemonde, engraved on copper, 1 m. 48 cm. 

 in width, 1 m. 11 cm. in height. Along each 

 side of the map, that is to saj', outside the 

 circle, is a table 30 cm. in width ; the first, on 

 the left, inscribed at the head, Tabula Prima, 

 and that on the right. Tabula Secunda. On 

 these tables are seventeen legendes, or inscrip- 

 tions, in duplicate, — that is to say, in Spanish 

 and in Latin, ■ — printed, and pasted on the map. 

 Each legend in Latin immediately follows the 

 Spanish original, and bears the same number. 

 Besides these seventeen inscriptions, there ai'e 

 five others in Spanish which have no Latin 

 exeniplairs. 



This ancient map, composed, as we shall 

 see farther on, in the year 1544, while Cabot 

 was yet living in Spain, contains geographi- 

 cal delineations of discoveries down to about 

 that period. In representing the north-east 

 coast of our continent, Newfoundland is laid 

 down as a group of islands ; and we easily 

 recognize the river and bay of St. Lawrence, 



