552 ADDENDA 



our account of the shad (p. 113), we give here a brief summary of his more important 

 conclusions, based partly on observational and partly on experimental data. 



Spawning in the Shubenacadie Kiver takes place chiefly in temperatures higher 

 than 12° C. (53.6° F.), and is temporarily interrupted if the temperature falls lower. 

 At 11 to 15° C. hatching takes place in 8 to 12 days, with the yolk sac absorbed in 

 4 to 7 days. Normal development of the eggs did not take place in water colder 

 than 7°. 



Leim's most interesting discovery is that larval development is more successful 

 in slightly saline water than in fresh, with about 7.5 per mille as the optimum 

 salinity. Notes are also given on the rate of growth of the larvae, and on their food, 

 as well as of the food of the maturing shad in the Bay of Fimdy, which consisted 

 chiefly of copepods and mysid slu-imps. 



Scale studies indicated a length of 10 to 14 centimeters at the end of the first 

 growing season, and of 20 to 25 centimeters at the end of the second, with the fish 

 maturing from four years of age on. 



Leim believes that the shad of the rivers tributary to the Bay of Fundy remain 

 for the most part within the latter whUe in salt water. 



Genus Myctophum, p. 149 



Goode and Bean's (1896, p. 511) report of the capture of Myctophum affine 

 Liltken (as M. opalinum) over the southeast slope of Browns Bank (lat. 42° 20' 

 N., long. 65° 07' W.) at 104 fathoms brings this genus within the geographic limits 

 of the Gulf of Maine. 



Myctophum resembles its near relative, the lanternfish (p. 149), in its general 

 appearance, having one short, soft-rayed dorsal fin, an adipose fin behind the latter, 

 a forked tail fin, the anal fin mostly or wholly behind the dorsal, large eyes, a wide, 

 very oblique mouth gaping back at least as far as the hinder margin of the eye, and 

 numerous phosphorescent organs on the sides. The longer snout and smaller 

 mouth of Myctophum, with the fact that the luminous organs on the snout are in 

 the form of small dots instead of a large patch covering the entire tip of the snout, 

 distinguish Myctophum from J5thoprora (p. 149). 



Many species of Myctophum have been described, all of small size, most of 

 them (perhaps all) dark colored and all living pelagic in the mid-depths of the 

 oceanic basins, where they are among the commonest of fishes, chiefly below 150 

 fathoms. 



The arrangement of the phosphorescent organs or spots affords the most useful 

 distinction within the genus, under which Brauer (Die Tiefsee-Fische. Wissen- 

 schaftliche Ergebnisse der Deutschen Tiefsee-Expedition, 1898-99 (1906), Band 

 XV, Teil I, p. 150) lists 20 odd from the North Atlantic north of 10° N. lat., any 

 one of which might stray within the 150-meter contom- abreast the Gulf of Maine. 

 However, only one has actually been taken within the limits of the gulf (noted 

 above), though others have been taken further out over the continental slope, and 

 since none of them has any real place in the Gulf of Maine fauna it seems needless 

 to burden this report with descriptions of them. Should one be picked up, we refer 

 its captor to Brauer (loc. cit.), or suggest that the specimens be submitted to the 

 United States Bm-eau of Fisheries for identification. 



