22 G Canadian Arctic Expedition, 191S-1918 



These larvae from Chantry island were orange (the labrum "kidney" 

 above the mouth parts being most strongly coloured), with black eyes, darker 

 intestine (food-particles) and pale appendages. I kept them alive for about a 

 month (Rearing No. 120) and on June 20, three days after being collected, they 

 were all in the metanauplius stage, and the smallest of them of the same size as 

 the biggest ones (see above) collected on June 17. Three days later their average 

 length was 5 mm.; and two weeks later they were from 4 to 9 mm. long; the 

 largest one could now be identified as an immature female, with an ovisac IJ 

 mm. long. These observations show the rate of growth of the younger stages 

 of this species, even in captivity, without food. They also show the unequal 

 lengths of the larvae, according to their date of hatching, a point already 

 emphasized under Lepidurus arcticus (p. 9). 



On this place it is interesting to record the hatching of one of the Branch- 

 inecta paludosa eggs collected (female animals) in a lake-pond at Bernard 

 harbour on August 10, 1915 (see p. 24). The eggs were kept in my laboratory 

 tent until the following spring (1916), in bottle of water (Rearing No. 94). 

 The water with the eggs was of course frozen solid for nine months (September 

 to May inclusive); nevertheless when it thawed out in the beginning of June, 

 1916, three of the eggs hatched and the nauplii emerged. Unfortunately I did 

 not observe them until the middle of the same month, when the larvae were 

 2 mm. long, and thus corresponding to those collected at the same time on 

 Chantry island (see above). I consider it very probable that the hatching of 

 these eggs took place one or two days before it happened that year in the ponds 

 where the ice would not melt as quickly as in a bottle. The experiment shows 

 definitely the hardiness of the eggs of this species, and that they form the means 

 of hibernating and propagating. 



On June 20, 1916, I collected in the brackish pond at Bernard harbour six 

 immature Branchinecta paludosa as representatives of the sizes found there 

 that date. They measured from 3 to 9 mm. in length, two of them (7, 85 mm.) 

 could be identified as males (claspers small), and two (8, 9 mm.) as females 

 with short ovisac without any eggs. The same -day I also secured in the shallow 

 pond on the sandflats (see Plate V, in Part J. of this volume) a few immature 

 mdividuals (5-10 mm. long), and ten older ones (9-14 mm.). The latter ones 

 were present in great numbers and of my specimens four are males, with big 

 claspers, and of a more pale orange colour than the females, and without the 

 dark purple-violet colour streak dorsally (see p. 19) ; while the females had olive- 

 green eggs in the ovisac. The main reason for the difference in size between the 

 specimens (from the same date) from the brackish pond, and those from the 

 shallow pond, probably is that the latter, owing to its position and character 

 melts earlier in the summer than the brackish pond, and more completely. 



On July 6, 1916, the Branchinecta paludosa in this shallow pond had attained 

 a size of around 15 mm. and fifteen of them were kept. Seven of these were 

 mature males and had big claspers, etc., while the rest were females with many 

 ripe eggs in the ovisac. 



Four days later I collected eighteen more specimens in the same brackish 

 pond; they measured from 7 to 15 mm., and five were males, the rest females. 

 Of the former one (7 mm.) had the second pair of antennae little developed (see 

 text figure 4g'), and no signs of external genitalia; another (13 mm.) both of these, 

 sexual characters better developed (as text figure 4i); while the three other 

 males (14-15 mm.) had the second pair of antennae and the genitalia fully 

 developed. Of the females the eight smallest (9-12 mm.) had the second pair 

 of antennae shorter than in the male of 7 mm. and a short ovisac without any 

 eggs (see text figure Ah). The five other females (13-15 mm.) had the larger 

 antennae (2nd pair), and the ovisac well developed, the latter with ripe eggs 

 inside. 



The water hole with brackish water near the beach west of Bernard harbour 

 examined July 14, 1916, contained besides many bright red Copepods (Eury- 



