1890.] MICHOSCOPICAL JOURNAL. 113 



pie process of experiment : and will, I am sure, amply repay whatever 

 of effort it may involve, in the supply of material available at any mo- 

 ment ; a thinj^ of no small account to any one who has been the victim 

 of disappointment just at the critical moment, which is no infrequent 

 occurence when depending upon fresh material for a special class de- 

 monstration. 



Concerning the question raised by Prof. Chaney in the article before 

 mentioned, as to its disposition toward living prey, I would record the 

 fact that I have seen it attack living prey very vigorously. Living earth- 

 worms dropped near its retreat, or dangling from a hook, were in- 

 stantly seized and eaten. I have noted the same disposition when con- 

 fined in aquaria. This fact does not in any way militate against the view 

 expressed of a seeming preference in some cases for a tainted diet. Such 

 it undoubtedly has, in common with many of its congeners of the open 

 beach and tide pools of the sea, where the habit may be observed at 

 almost any time. What was before said of its disposition toward living 

 animal prey will apply equally to growing vegetation ; the stomachs 

 of cray-fishes dissected containing fresh and green vegetable matter. 

 Moreover, I have repeatedly fed cray-fishes in the aquaria with growing 

 algaj and pond-weed which were voraciously devoured in lai'ge quan- 

 tities. 



Concerning the habits of reproduction there are various opinions en- 

 tertained by observers, which would indicate that either this habit varies 

 greatly in diftbrent localities, or that grave mistakes have been made by 

 careless observers. It is not unlikely that something of both, together 

 with the slightly varying habits of difterent species, may in a measure 

 account for this difterence. 



That they will breed in confinement the following facts clearly demon- 

 strate. 



During the spring iSSS, I captured a large number of full-grown speci- 

 mens of cray-fishes, chiefly of the species of Cambarus gracilis and C. 

 obesus, of both sexes, immediately upon the breaking up of the severe 

 winter of that year, and their first issuance from the state of hibernation. 

 They were placed in roomy ac[uaria where they remained for several 

 weeks. During this time several pairs were found in copulation. 



I have also in excellent state of preservation larval cray-fishes of the 

 same species which were hatched in my aquaria, and were apparently 

 as active and normal as those hatched in the natural habitat of the ani- 

 mals. It should be stated, however, that in this particidar case the eggs 

 had been laitl before the mother was placed under the artificial condi- 

 tions indicated, and that the young were hatched within a fortnight of 

 the change. Whether the entire cycle from copulation to ovipositing and 

 hatching might occur I am not prepared to state from actual observation. 

 I have made the same observations upon the common shrimp, Crangon 

 vulgaris, but not including the entire cycle of development. It would 

 seem to be very strongly indicated therefore that with ordinary care thev 

 would freely breed to perfection under conditions of confinement. 



There are likewise various accounts as to the mating season in dificrcnt 

 localities, due perhaps to reasons before suggested. Huxlev indicates 

 the season of mating as '• October, or earlier for English species," while 

 the months of November, December, and January are reported as the 

 season in France. The facts cited already as to this process under arti- 

 ficial conditions would indicate a wide difi'erence as to the habit among: 



