712 



SCIENCE 



[N. S. Vol. XXIX. No. 748 



electrical charge — the granules unfailingly moving 

 toward the anode when placed in an electrical 

 field of light intensity. The author thinks this 

 explains not only the movements of independent 

 granules, but the movements of some chromato- 

 phores as a whole — as for example the skin chro- 

 matophores of lower vertebrates and the retinal 

 pigment of arthropods and vertebrates. And, 

 finally, this fact is of very considerable impor- 

 tance in a consideration of the physiology of color 

 inheritance. 



The Rate of Digestion in Cold-blooded Tertelrates 



in Relation to Temperature: Oscae Riddle, 



University of Chicago. 



By the use of Mett's tubes and a constant tem- 

 perature tank, information was sought and ob- 

 tained from cold-blooded vertebrates on the fol- 

 lowing points : ( 1 ) A definite measure of the 

 rapidity of digestion, (2) comparison of this rate 

 in fishes, amphibians and reptilia, (3) seasonal 

 variations in digestive power, (4) a direct and 

 definite measure of the efi'ect of raising or lower- 

 ing the temperature of the animals, on their rate 

 of digestion, (5) the temperature coefficients of 

 digestion in these animals. 



It appears that a gradual loss of digestive 

 capacity has occurred in the amphibia and rep- 

 tilia during their evolution; and the bearing of 

 this fact on the development of warm-bloodedness 

 in the vertebrata seems to merit attention. 



The Hyo-iranchial Apparatus of Typhlotriton: 



Wm. a. Hilton, Cornell University, Ithaca, 



N. Y. 



The hyo-branchial skeleton of Typhlotriton 

 spelceus in the adult resembles Spelerpes rather 

 than members of the family Desmognathidse in 

 which it has been placed. The hyo-branchial 

 skeleton of the larva resembles Spelerpes much 

 more than the larva of Desmognathus. Like 

 Spelerpes it has but three branchial arches, while 

 Desmognathus has four. 



Typhlotriton is a cave form, but from its eyes 

 and other structures it seems to have much more 

 recently come to such an environment than 

 Typhlomolge. The hyo-branchial apparatus of 

 Typhlotriton larva is almost the same as that 

 of the supposed adult, but possible larval form 

 of Typhlomolge. 



A series of apparently related species beginning 

 with those living in caves only to a slight degree 

 and ending with those best adapted to a sub- 

 terranean life, is as follows: (1) Spelerpes longi- 

 ca/udus, (2) Spelerpes maoulioaudus, (3) Typhlo- 

 triton spelceus, (4) Typhlomolge rathbuni. 



Some Egg-laying Habits of Amphitrite : John W. 



Scott, Kansas City, Mo. 



( 1 ) The egg-laying reflex of A. ornata is closely 

 associated with the time of spring tide, the height 

 of any given period of egg-laying always occurring 

 within three days of the time of new or full moon. 

 In early summer the period of sexual activity 

 tends to occur after, in late summer before, spring 

 tide. (2) Eggs and sperm float free in the body- 

 cavity, and are usually in various stages of devel- 

 opment. Ripe eggs show the metaphase of the 

 first maturation spindle, and eggs in this stage 

 have a greater density than unripe eggs. It is 

 entirely probable that the apparent selection of 

 ripe and rejection of unripe eggs by the nephridia 

 is due to the different effects produced by ne- 

 phridial currents upon bodies of differing densities. 



Bilateral Symmetry in the Development of the 

 Primary Septa of a Living Coral: J. W. Mavoe, 

 Cambridge, Mass. 



The usual bilateral symmetry in the develop- 

 ment of the first six pairs of mesenteries is shown 

 to occur in Agaricia fragilis. The six primary 

 septa are found to be arranged about a plane of 

 bilateral symmetry which is the same as that for 

 the soft parts, and the exosepta are found to arise 

 in bilateral pairs. The bilateral symmetry of the 

 primary septa is found to persist in later stages 

 with well developed epitheca and exosepta. The 

 arrangement of the primary septa in Agaricia is 

 different from that in Siderastrwa radians as de- 

 scribed by Duerden, but agrees with that in 

 Lophophyllum proliferum as described by the 

 same author. 



Autotomy of the Hydranth of Tubularia: Max 

 MoBSE, College of the City of N. Y. 

 Hydroids commonly absorb their hydranths 

 when placed under artificial conditions. Tubu- 

 laria is an exception, and pinches off the hydranth 

 entirely from the stem. Later it regenerates a 

 new hydranth. There is no disintegration of the 

 cells until after the hydranth has fallen off. Tem- 

 perature is the active factor in inducing the 

 process; hence Tubularia naturally occur fully 

 developed at certain definite periods. 



Role of the Nerve System in Regeneration in 

 Earthtcorm and Neivt: A. J. Goldpaeb, Colimi- 

 bia University. 



The accumulated evidence points to the conclu- 

 sion that early embryos and larvae can regenerate 

 missing organs independently of morphogenic in- 

 fluences exerted by or through the nerve system. 

 Concerning the role of the nerve system in adults 



