738 



SCIENCE. 



[N. S. Vol. XXI. Xo. 541. 



utmost importance in the debated question 

 of discontinuous versus blended inheritance. 

 Although, as has just been said, the rough 

 coat dominates in the first generation of 

 hybrids (rough X smooth), yet sometimes it 

 shows a weakened condition ; and what is even 

 more interesting is that certain smooth indi- 

 viduals which may be said to be prepotent 

 show a stronger tendency to weaken the rough 

 coat than do other individuals. Such par- 

 tially rough individuals may later transmit 

 the rough character to their offspring in its 

 full intensity. . Again, repeated crossing of 

 rough animals with prepotent smooth ones 

 leads to a further weakening of the rough coat 

 until it may be almost eliminated. Here are 

 some nuts to crack for those who believe the 

 Mendelian purity of the germ cells depends 

 on the elimination of maternal or paternal 

 chromosomes which have never mixed during 

 their sojourn in the same nucleus ! 



Another apparent Mendelian inconsistency 

 is found in the ratio of inheritance of the 

 long coat, which is dominated by the short, 

 or ordinary coat. In the second generation 

 of inbred hybrids the proportion of long coated 

 individuals exceeds the expected number. 



An interesting point in regard to heredity 

 in rabbits is shown when pure white and 

 Himalayan rabbits are crossed. The Him- 

 alayan character dominates in the first gen- 

 eration only imperfectly, yet complete segre- 

 gation of the characters takes place in the 

 germ-cells, so that the two pure parent types 

 reappear in some of the offspring. 



For other important facts the paper itself 

 must be consulted. That some of the con- 

 clusions are only tentative the author himself 

 fully realizes. The constant attention and 

 great labor involved in an extended experi- 

 ment of this sort will be appreciated by those 

 who have had experience in such matters, and 

 we can confidently expect the future to bring 

 forth many important results from these pedi- 

 gree animals. Alread.y enough ' problems ' 

 are indicated to engage many other workers 

 who have the opportunity, the patience and 

 the skill to give to investigation of this sort. 

 Carefully recorded histories, such as is given 

 for these hybrids, are invaluable to science. 



Professor Castle is to be much congratulated 

 upon his admirable work. 



T. H. Morgan. 



Columbia UNn-ERsiTY. 



The Stone Reefs of Brazil, their Geological 

 and Geographical Relations, with a Chapter 

 on the Coral Reefs. By Johx Casper Brax- 

 NER. Bulletin of the Museum of Compara- 

 tive Zoology, Vol. XLIV. (Geological series^ 

 Vol. VII.). Cambridge, Mass. May, 1904. 

 This important memoir treats of a geolog- 

 ical phenomenon that has not hitherto received 

 the attention that its importance and interest,, 

 both commercial and scientific, deserve. A 

 port formed by a stone reef harbored in 1500' 

 the fleet of the first Portuguese discoverers of 

 Brazil and the impression produced by it on 

 their minds is strikingly shown by the fact 

 that they applied to it a descriptive title, 

 ' Porto Seguro,' instead of a name taken from 

 the Saint's Calendar, as was the almost uni- 

 versal custom of the early Iberian explorers. 

 From this point as a center a considerable 

 section of the Brazilian coast region was ex- 

 plored and peopled, while two other stone-reef- 

 protected ports, Recife (Pernambuco) and 

 Rio Grande do ISTorte, became equally or even 

 more important in the history of the early 

 development of the country. The first of these 

 has retained its commercial importance to the 

 present day, and, being situated on a great line 

 of travel, has attracted the attention and ex- 

 cited the wonder of all mariners and travelers 

 who have visited the Brazilian coast. The' 

 former very naturally confounded the reefs 

 formed by sandstone with those, still more- 

 frequent along this coast, composed of coral 

 rock, and the latter have repeated the sailors' 

 statements to the effect that a large section of 

 the coast is bordered by a reef of the same 

 nature as that of Pernambuco. 



The first to accurately describe the Per- 

 nambuco reef as a consolidated bar of sand 

 was Darwin, who touched there in the cele- 

 brated voyage of the Beagle. Hartt, in 1870, 

 showed that the reputed great barrier reef of 

 Brazil was a myth, though detached reefs, 

 both of coral and of sandstone rock, occurred 

 at numerous points ; the latter being due to a 

 superficial consolidation of beach sands which 



