34 



NATUEAL SCIENCE NEWS. 



is much to be regreted that the 

 large mass, of which the record 

 seems to me to be entirely reliable, 

 cannot be rediscovered. — Amer. 

 four. 



Exfoliation in the Tortoise. 



By Dr. Morris Gibbs. 



For many years much interest 

 has attached to the process of 

 skin-shedding in the reptilian order. 

 This periodical exuviation is a well 

 known condition to most of our ob- 

 servers, and the process with ser- 

 pents has been extensively written 

 upon. But the writer is not aware 

 that desquamation has often been 

 observed in the bony-shelled rep- 

 tiles. It is to be doubted if the 

 process ever occurs as a periodical 

 condition with our turtles and ter- 

 rapins at the North, and probably 

 not in warmer latitudes. 



During several seasons a number 

 of specimens of so-called turtles, 

 terrapins and tortoises of various 

 common species, were studied in 

 confinement. But they never gave 

 evidence of shedding the epider- 

 mal scales, and neither could it be 

 ascertained that these creatures ex- 

 foliate in the wild state. 



Variations from normal habit of- 

 ten gives rise to peculiar condi- 

 tions, and a change in the condi- 

 tions which surrounded a common 

 Box Tortoise, Cistuda Carolina 

 ( Linn. ), gave me the opportunity 

 of noting desquamation, and draw- 

 ing conclusions. As the process 

 was an interesting one, and has 

 not been described, so far as I can 

 learn, a short sketch will be given. 



All of our reptiles at the north, 

 so far as known, hybernate during 

 at least five months of the year. 

 This tortoise follows this habit — 

 going into seclusion in the dead 

 leaves and mold in October and 

 emerging from its retreat in the 

 following April. I have observed 

 the habit repeatedly in both the 

 wild as well as with the confined 

 individuals. 



A young friend of mine owned a 

 Box Turtle, and at the beginning of 

 cold weather took his pet within 

 doors. It fed, as usual, entirely on 

 vegetables, preferring celery shoots 

 to all other food. The house was 

 steam-heated, and the even tem- 

 perature kept the tortoise active 

 throughout the winter. 



During the coldest part of the 

 season, Dick, as he was called, be- 

 gan to shed his plates. This act 

 was in no way accompanied by evi- 

 dence of disability, as the creature 



was active throughout the process 

 of desquamation and continued to 

 eat as usual. The neural plates, 

 as they are called, those lying over 

 the line of the spine, loosened first, 

 the costals or rib-plates next and 

 the small marginals last on the 

 carapace, or upper shell. The 

 plates of the plastron or lower 

 shell next exfoliated, and fell off 

 irregularly and not in order. 



At the time these plates came a- 

 way the framework, or shell prop- 

 er had the usual appearance of de- 

 nuded bone, and especially re- 

 sembled the appearance of the 

 human skull when the scalp is re- 

 moved. The blush or redness de- 

 parted within a couple of days, 

 and the shell soon assumed the ap- 

 pearance of a dead bone. 



In the shedding of the skin with 

 snakes, the act is a simple slough- 

 ing of the external integument, and 

 does not involve the true skin in 

 any way. This is evident if we ex- 

 amine the shed skin, or mask, as it 

 is called. We find that the out- 

 side or scarf-skin, as we call it 

 in the human, does not possess any 

 pigment, and the slough from the 

 snake holds no colors, while the 

 inner coat or new dress of the 

 snake is very bright. But in the 

 case of desquamation in this tor- 

 toise, all formed pigmentary mat- 

 ter came away, and left nothing but 

 the bone surface. I have occasion- 

 ally found small water turtles, chry- 

 smys, with loosened spidermal plates 

 on the carapace, but other plates of 

 brighter color were found beneath. 



After a week or ten days a dusky 

 spot was seen, and shortly, other 

 spots. These spots, first observed 

 in the tract of the neural plates, at 

 last came to be distinguished as 

 centers of growth in the scales, or 

 outside covering. The approxi- 

 mate center of the prospective 

 plate could be told, as there was a 

 slight groove where the plates 

 joined, showing on the denuded 

 surface of the ribs. As is well 

 known, the plates do not corres- 

 pond in shape, size or number to 

 the vertebrae or ribs, and the cen- 

 ters of their growth are not in- 

 fluenced by the centers of ossifica- 

 tion. 



In time, as the dusky markings 

 became more pronounced, and the 

 renewal became general, the yellow 

 spots began to show. It time, the 

 completely denuded ■ surface was 

 fully re-covered with regulation 

 plates, which exactly represented 

 the original excepting that the col- 

 ors were brighter. The time oc- 

 cupied in the complete re-forming 

 of this new growth was all of ten 



weeks. The tortoise was in no way 

 incapacitated during the process, 

 and it continued to live and thrive, 

 and making its usual attempt to 

 escape in the spring. It is possible 

 that this creature was not healthy, 

 and possibly that deprivation of 

 its habit of hibernation induced a 

 marked deviation in conditions of 

 life, with accompanying changes, 

 little known to observers. 



This example shows that com- 

 plete exfoliation may take place in 

 the tortoise. It is not impossible 

 that this process may be an oc- 

 casional feature of the animal's 

 growth. In any event, it indicates 

 that a cold-blooded vertebrate can 

 be completely denuded of covering, 

 to its bones, and regain its condition, 

 which is. in itself, a remarkable 

 feature — either as a natural one or 

 reparative process following ravag- 

 es of disease. 



In this instance, we have, per- 

 haps, an illustration of the repara- 

 tive process that follows the denud- 

 ing of a species of the South, when 

 the tortoise shell is removed by 

 mechanical means. Strictly speak- 

 ing this instance cannot be called 

 exfoliation, as it involved tissue 

 beneath the epidermal integument. 



Kalamazoo, Mich. 



The Marine Biological Labora- 

 tory at Wood's Holl. 



The laboratory at Wood's Holl 

 differs in one important respect 

 from other seaside laboratories, 

 such as the well-known station at 

 Naples. Our American laboratory 

 combines the function of a station 

 for research with that of one for in- 

 struction, while that at Naples is ex- 

 clusively for original investigation. 

 Any one who intends to enter upon 

 any line of research, but is unpre- 

 pared in the details of technique, 

 may acquire such preparation in 

 the school at a great saving of 

 time and energy. The school is al- 

 so made use of by teachers who 

 wish to keep up their knowledge of 

 biology and the methods of study. 

 For their benefit classes have been 

 organized in vertebrate and inver- 

 tebrate anatomy, embryology, mor- 

 phology, comparative physiology, 

 and botany. The class in embry- 

 ology studies the fertilization, seg- 

 mentation, and e; rly stages of de- 

 velopment of various pelagic fish 

 eggs, with the variations produced 

 by securing abnormal conditions of 

 pressure, rupture of cell mem- 

 brane, etc. ; it learns the method 

 of killing, staining, imbedding in 

 paraffin and celloidin, and recon- 



