300 'Journal of Comparative Neurology and Psychology. 



it up when the crayfish have had time to gather. Abbott ^ says 

 that they He in wait under stones for ethestomoids or "darters," 

 which they seem to be very skillful in catching with their chelae. 



Putnam^ contrasts the reaction of Combarus bartonii to food 

 with th?t of Cambarus pellucidus, the blind crayfish. 



The moment the water in its jar is disturbed the eyed species rears itself upon 

 its tail, throws out its large claws, seizes the piece of meat, or bread, and hastily 

 conveying it to its mouth, generally holds on to the morsel until it is all eaten; 

 though sometimes this species will take but a bite or two and then drop the food, 

 and I do not think it will touch the same piece again. The blind species, on the 

 contrary, darts back as soon as the food is dropped into the water and then 

 extends its antennae and stands as if on the alert for danger. After along while, 

 sometimes from fifteen to thirty minutes, it will cautiously crawl about the jar 

 with its antennas extended as if using them for the purpose of detecting danger 

 ahead. On approaching the piece of meat, and before touching it, the animal 

 gives a powerful backward jump and remains quiet for a while. It then cau- 

 tiously approaches again, and sometimes will go through this performance three or 

 four times before it concludes to touch the article, and when it does touch it, the 

 result is another backward jump. After another quiet time it again approaches, 

 perhaps only to jump back once more, but when it finally concludes that it is 

 safe to continue in the vicinity of the meat, it feels with its antennae for awhile, and 

 then it takes the morsel in its claws and conveys it to its mouth. I have twice 

 seen the meat dropped as it was passed along the base of the antennae, as if the 

 sense of smell, or more delicate organs of touch seated at that point, were again 

 the cause ot alarming the animal. When the jaws once begin to work, the piece of 

 meat, or bread, if very small, is devoured, but if too large only a few bites are 

 taken and the food is dropped and not again touched, though the animal then 

 crawls over it and rests upon it without being in the least concerned. 



Graber^ experimented upon various animals w^ith chemicals, 

 and found that Pagurus and Palinurus pay no attention to oil of 

 roses, which is extremely disagreeable to most animals. Pagurus 

 reacted to asaf^^etida by sinking one of its long eye-stalks every two 

 to four minutes, and wiping it with its maxillipedes. Sometimes 

 both eyes were lowered at once. The antennae and the tail fan 

 showed no reaction. 



^Abbott, C. C. Notes on the Habits of Certain Crayfish. American Naturalist, Vol. 7, pp. 30-34. 

 1873. 



'Putnam, F. W. Remarks on the Mammoth Cave and some of its Animals. Proceedings of the 

 Society of Natural History, Boston, Vol. 17, pp. 222-225. '^75- 



^ Graber, V. Ueber die Empfindlichkeit einiger Meerthiere gegen Riechstoflie. Biologisches 

 Centralblatt, Vol. 8, pp. 743-754. 1889. 



