666 



if not in all Cambari and is probably a real dimorphism and not an 

 alternate phase in the life of each individual, as is the apparent dimor- 

 phism of the males in this genus. 



Most of the males were about 25 mm long: one was 32, one 33, 

 two 17 and one 14. Many of the females were about 28 mm long: many 

 28: three sinistral forms were 31, one 17, one 16: of the right handed 

 females one was 36, two 35, one 32, one 31, one 21, two 20. 



That the breeding season is a somewhat extended one, or at least 

 not punctually observed by all females alike, is shown by the various 

 phases present in this small collection. In some males the sperm was 

 found in the tip of the stylet of the first abdominal somite, which indi- 

 cates a recent union with the female and this usually takes place some 

 weeks or months before the eggs are laid, in CambarKs, yet females were 

 found bearing eggs. Again while some of the females bore eggs that 

 were evidently but recently laid, since they had short flat stalks and no 

 visible embryo, other females bore eggs that must have been laid much 

 sooner since the embryos had advanced far enough to show nine pairs of 

 appendages as in Reichenbach's stage H, and in another case the appen- 

 dages were as in stage J, long and crowded. On a few females larvae 

 were found and this means, probably, that their eggs had been laid some 

 weeks before. However, the majority of these specimens had not yet 

 entered their breeding period, to judge from their smaller size and from 

 the large ovarian eggs still present in some of them. Only six females 

 bore eggs; three sinistral, 31 mm long and three dextral, 31, 32, 35 mm 

 long. Only two females, both dextral, bore young, and these females 

 were 35 and 36 mm long. 



Hence it may be that the breeding seasons begins before July, for 

 some larger females and continues after July for others, possibly much 

 longer, but one of the males had recently cast its shell and some of the 

 females had the new shell well formed under the old, which would indi- 

 cate an approach to the end of the breeding season, for these specimens 

 at least. 



The eggs were about 1 Ya i^i^i iii diameter, which is not actually 

 large for crayfish eggs, but relatively large for such small adults, for 

 the width of the abdomen between the pleural plates was but 9 mm and 

 the length of the body 35 mm. More than 120 eggs were fastened onto 

 the eight pleopods, about 15 on each, and while this is not a large num- 

 ber of eggs for one female as compared with what is found in some of 

 our Northern crayfish it filled out the abdominal basket as completely, 

 since the eggs were so relatively large. 



None of the eggs were found attached to the first abdominal somite, 

 either by hairs or by pleopods and a search for the expected first pleo- 



