October 3, 1902.] 



SCIENCE. 



555 



This cat is a female and has borne three lit- 

 ters with normal fathers. Fifty per cent., as 

 the owners remembered, were abnormal in one 

 litter. The sole survivor has twenty-four toes, 

 six on each manus and pes, all practically 

 equivalent. In another litter more than 

 fifty- per cent, were abnormal; the sole sur- 

 vivor, a male, has the digit formula of 



6 le 



with a total of twenty-five toes. In the third 

 litter there are five kittens. Three are ab- 

 normal, with the following formulae : 



5 5' 



4 4 



5 5 



The last formula represents the number of 

 digits when the kitten was a few days old. 

 The first (inside) digit on one pes has now 

 totally disappeared, and the corresponding one 

 on the other pes is fast shriveling away; so 

 that the normal number on each pes is being 

 secondarily established by a resorption of 

 No. 1, the toe which is normally absent on the 

 pes and reduced on the manus. 



In each of the four instances in which seven 

 toes appear on one foot they are arranged in 

 two groups. Toes Nos. 7, 6, 5, 4 (7 being the 

 outermost toe) resemble the main four toes of 

 the normal manus (i. e., 5, 4, 3, 2). Of 

 the three constituting the second group No. 

 2 is larger than any of the other six toes. 

 Nos. 1 and 3 are of about equal size and 

 smaller than any of the other five. Nos. 1, 2 

 and 3, taken together, seem to form a second 

 (supernumerary) foot. It is interesting that 

 seven toes occur only on a manus, which had 

 normally more toes than the pes. The fact 

 that the fifth toe degenerated in one case on 

 the inside of the pes indicates that the super- 

 numerary toes are added on the inside of the 

 foot. This probably does not hold when there 

 are two supernumeraries on the manus (seven 

 in all), where, as Poulton held, the innermost 

 toe may represent the hallux, or the super- 

 numeraries may be interpreted as Freeland 

 Howe, Jr., has recently {Am. Nat., July, 1902) 

 interpreted them in six-toed feet. According 

 to this interpretation the outermost three toes 

 are comparable to digits 3, 4, 5, of the normal 



pes. None of the other three individually 

 represent Nos. 1 or 2, but collectively they re- 

 place No. 1 plus No. 2. This seems to me the 

 more probable view in the present instance. 



A review of the above facts shows the marked 

 prepotency of the sport. The grandmother 

 (generation I.) had 



5 I 5 



or 22 toes. In generation II., one litter con- 

 tained but one abnormal kitten among five 

 (twenty per cent.), with a total of 22 toes. 

 The other litter contained several abnormal 

 ones, the sole survivor possessing seven toes 

 on one manus, though with a total of but 21. 

 From this cat have arisen the three litters of 

 generation III., in which one has 25 toes (one 

 manus having 7), two have 24 (one of these 

 having 7 on each manus), and all three litters 

 possessed not less than fifty per cent, of ab- 

 normal individuals, the last having sixty per 

 cent. It is clear that the total number as 

 well as the number on each manus and pes is 

 increasing from generation to generation. 



There seems to be a no less remarkable pre- 

 potency of sex. The male cat with 25 toes, 

 when crossed with normal females, seems to 

 have had no influence on the number of toes 

 in the offspring, so far as information could 

 be obtained. This result is not in harmony 

 with Poulton's observations, however, and may 

 not be borne out by further information. 



I have obtained several of these cats for 

 breeding and future study. 



Harry Beal Torrey. 



Zoological Laboratory, Univ. of Cal., 

 Berkeley, Cal., Sept. 6, 1902. 



MAGNETIC WORK OF THE UNITED STATES COAST AND 

 GEODETIC SURVEY PLANNED FOB JULY 1, 



1902, TO JUNE 30, 1903. 



(a.) Land Magnetic Survey Worh. — The de- 

 termination of the three magnetic elements at 

 four hundred to five hundred stations dis- 

 tributed principally in Virginia, New Jersey, 

 Pennsylvania, Ohio, Michigan, Kansas, Ne- 

 braska, Texas, Arkansas and Florida. 



(b) Magnetic Observatory Worh. — The con- 

 tinuous operation of the four magnetic observ- 



