672 



SCIENCE. 



[N. S. Vol. XV. No. 380. 



Basset hounds ; but with this exception the 

 important law advanced more than a dozen 

 years ago has not, up to this time, received 

 a careful analysis of a large number of 

 pedigrees, of three or more genei-ations. 



Our work was carried on with data ob- 

 tained from the American Kennel Club 

 Stud Books and includes 390 dogs, of the 

 pointer breed, of which 660 parents, 1,367 

 grandparents, 1,361 great-grandparents 

 and 978 great-great-grandparents are 

 known. Four sets of color characteristics, 

 namely, liver or no liver, black or no black, 

 white or no white, and ' ticked ' or not 

 ' ticked, ' were considered. By the method 

 used no substitutions were needed to fill 

 the gaps left by unrecorded ancestors of 

 the first four degrees. The results showed 

 an almost perfect harmony, in each in- 

 stance, between the facts and Galton's law, 

 the greatest real deviation being only 1.1 

 per cent., while the least was .4 per cent. 



Astrosphere and Centrosome in the Fertili- 

 zation of the Egg of Phascolosorna (P. 

 vulgare and P. Gouldii) : J. H. Ger- 



ROULD. 



The Larval Development of Phascolosorna: 

 J. H. Gereould. 



On the Ova of Ophidia: E. L. Mark and 

 C. A. Crowell. 



A System of Ahbreviations for the Letter- 

 ing of Anatomical Figures: E. L. Mark. 



The Circulatory System of Lamellibranchs : 



G. A. Drew. 



By careful injections, preparations and 

 dissections, the vascular system of the large 

 northern scollop, Pecten tenuicostatus, has 

 been found to be extensive and definite. In 

 the mantle, for example, the blood vessels 

 branch repeatedly and form a very fine net- 

 work that in appearance is much like a 

 capillary plexus. Prom this plexus the 

 blood is collected directly by vessels that 

 join to form the vein that, in common 



with the efferent vessels from the gills 

 of the corresponding side, returns the 

 blood to the heart. Inasmuch as some 

 of the coloring matter of the injecting fluid 

 finds its way out of the vessels and into the 

 surrou.nding tissue, it seems quite possible 

 that the blood may function directly as 

 lymph. Large lacunte, such as are gener- 

 ally supposed to be present in Lamelli- 

 branchs, have not been found. The vessel 

 that supplies the foot is capable of great 

 distention, and offers the same for the 

 profusion of the foot, but the vessel is 

 very definite in shape and is not compara- 

 ble to a lacuna. The course taken by the 

 blood in its circulation is essentially the 

 same as has been described for other forms, 

 but the vessels seem to be much more finely 

 branched, and the circulatory system much 

 more nearly ' closed ' than has generally 

 been supposed to be the case with Ijamelli- 

 branchs. 



On the Anatomy of a Double Monster: 

 H. L. OsBORN. (Read by title only.) 

 A calf born near Minneapolis, Minn., in 

 1901, and which lived only a few minutes, 

 came to my notice and proved interesting 

 as a nearly complete twin formation. 

 There is a single umbilical opening and 

 cord, there are two functional hind legs 

 and a single anus, but there are two tails 

 and a third hind leg carried in the mid- 

 dorsal line, and projecting backward. 

 Anteriorly there are two complete animals, 

 two heads, thoraces and two anterior 

 abdominal regions completely developed. 

 There is a single abdominal cavity pos- 

 terioi'ly, but most of the viscera are 

 double. There are two spinal columns, 

 each sacrum articulates externally with a 

 complete half pelvis, and these meet below, 

 forming a symphysis, and on its opposite 

 side each sacrum articulates with an ilium 

 which meets a very imperfect ischium, so 

 that here the division of the embryonic 



