168 



SCIENCE. 



[N. S. Vol. XI. No. 266. 



On the development and morphology of the ac- 

 tual skeleton of vertebrates : Chaeles S. 



MiNOT. 



The author reported observations upon 

 the embryos of man and other mammals, 

 of the chick, and of fishes, which demon- 

 strate the existence of a continuous carti- 

 laginous perichordal rod, for which the 

 term chondrostyle is proposed. The chon- 

 drostyle is probably the primitive stage, 

 out of which the chondrocranium is de- 

 veloped where there are no myotomes, and 

 out of which vertebral arches, and later ver- 

 tebral bodies are developed, where the 

 myotomes are persistent. 



The arrangement of the mammary glands in 

 litters of unborn pigs : Q. H. Parker and 



C. BULLARD. 



An examination of 1000 litters of unborn 

 pigs showed that the numbers in the litters 

 varied from one to fifteen, the most usual 

 number being six. As there were in all 

 5970 pigs the average number per litter 

 was 5.97. Of the 5970 pigs examined, 2947 

 were females and 3023 males, or for every 

 1000 females there were about 1026 males. 

 In the males the nipples varied from nine 

 to eighteen, the most usual number being 

 twelve and the average 12.434. In the 

 females the nipples varied from eight to 

 eighteen, the most usual number being 

 twelve and the average 11.908. Litters of 

 eight or less would always find ample milk 

 accommodations. Litters larger than eight 

 might be too numerous for the best milk 

 accommodations, and as the number of 

 nipples is not significantly larger in litters 

 of large size than in those of small size, 

 this lack of adjustment must at times be 

 realized. 



In abnormal carapace in the sculptured tortoise : 



G. H. Parker. 



An abnormal carapace of the common 

 sculptured turtle showed at the posterior 

 end of the series of marginal scutes, both 



right and left, two scutes in place of three, 

 and in the middle of the carapace five bony 

 segments in place of six. The variation in 

 the bony segments is in mesodermic struc- 

 tures and lies anterior to the region of 

 scute variation which is in ectodermic 

 parts. As the ectoderm in tadpoles is 

 known to migrate posteriorly over the 

 mesoderm, it is possible that the same may 

 occur in turtles and that the two regions of 

 variation separated in the adult may have 

 been in an earlier stage at the same trans- 

 verse plane and induced by the same cause. 



The trigemino-facial ganglionic complex of 

 Gadus and Amiurus : C. Judson Herrick. 

 The details of the composition of this com- 

 plex as worked out by the author in Menidia, 

 difler in some respects from those given by 

 most other recent students of the cranial 

 nerves of fishes. He accordinglj', for pur- 

 poses of control, worked out microscop- 

 ically on Weigert sections the composition 

 of the trigemino-facial complex in the cod- 

 fish very fullj' and of the cat-fish somewhat 

 less exhaustively. In both of these cases 

 the results of this examination show very 

 clearly that the plan of these nerves, and 

 indeed of the peripheral nervous system as 

 a whole, is fundamentally the same as in 

 Menidia, with only unimportant variations 

 in detail. 



In Gadus and Amiurus the trigeminus 

 is as in Menidia, save that the Gasserian 

 ganglion is intra-cranial. In all of these 

 types the facialis has three roots, motor, 

 lateralis and communis, the latter being 

 large in Gadus than in Menidia, and much 

 larger still in Amiurus. In Gadus the 

 geniculate or facial ganglion is crowded 

 close to the Gasserian, yet clearly separable 

 from it. It is intra-cranial and gives rise 

 to the same nerves as in Menidia, except 

 that it contributes nothing to the hyoman- 

 dibular trunk and does contribute to the r. 

 mandibularis V. The sympathetic system 



