742 General Notes. [August, 
are quite unlike those of the adult both in form and size. The 
modifications of this pair of appendages, indicating the sex of the 
individual, have not yet appeared, however, and are probably not 
developed until after the next or seventh molt, when the young 
lobster entered upon the eighth stage of its free existence. There 
is a very decided inequality in the size of the two great “claws” 
or “ pincers” at the end of the seventh stage. The young animal 
now manifests a more strongly marked disposition to remain on 
the bottom than during the preceding stage. This last-described 
stage is attained in about seven weeks after hatching. 
It will be seen that as to the number of stages my observations 
are not in accord with those of either Smith or of Dannevig.' 
The work of G. O. Sars, on the development of the European 
lobster, I have not seen, but the large amount of material which 
I have had the opportunity to study in a series of tanks, under 
conditions admitting of very little chance of error, in the United 
States Fish Commission station at Wood’s Holl, leads me to think 
that with the precautions which have been taken, I have not con- 
founded or subdivided any stages, as I believe an alcoholic series 
which has been preserved of the stages above described will 
„amply prove. With a slight rise in the temperature of the water, 
-and an abundance of food, the fourth molt, or fifth stage, may be 
rr in twelve days, as later expericnce shows.—/ohn A. 
J 
_ THE MONSTROSITIES OBSERVED AMONGST RECENTLY HATCHED 
LoBSTERS.—At Wood’s Holl a few double monsters were hatched 
out amongst the normal lobster larvae. These monstrosities were all 
_ the more interesting from the fact that they proved in the most 
striking manner that double monsters must be developed in the 
= meroblastic egg of the lobster in much the same way as in that 
-of fishes. 
_ Four forms of double monsters were observed : ‘ h 
_ First type—This one had no eyes ; the cephalothoraces of the 
_ two embryos were completely fused together laterally and anteri- 
orly, while their abdomens were separate and diverged at a wits 
angle from each other. th 
__ Second type—This form had a single eye anteriorly and on so 
line where the cephalothoraces of the two embryos were i 
together; in other respects this form resembled the preceding. $ 
-Third type—In this form the cephalothoraces of two eo 
were fused laterally and anteriorly, and there was no median €y 
as in the preceding type, but a pair of eyes, the one represo 
the left eye of the left embryo, and the other the right eye ° 
right embryo, were developed. b 
_ Fourth type —In this form the cephalothoraces of two em n 
se Saltvandsfisk- 
Beretning over Virksomheden ved Udklaekningsanstalten for 
