ADDENDA 



Mackerel shark (Isurus punctatus Storer), p. 36, and Porbeagle (Isurus nasue 



Bonaterre), p. 36 



The Halcyon recently caught, on Platts Bank, a mackerel shark indistinguish- 

 able from Isurus punctatus except that its teeth were denticulate like those of the 

 European I. nasus instead of smooth, as Garman (1913) describes and figures them 

 for /. punctatus. In the face of this capture, it is no longer possible to maintain a 

 North American smooth-toothed species as contrasted with a north European 

 with denticulate teeth (p. 36). Either the two intergrade, in which case the com- 

 mon mackerel shark of our waters must be known as 7. nasus, or, if they are actually 

 distinct, both of them occur in the Gulf of Maine. W. C. Schroeder is now engaged 

 on a revision of the mackerel sharks of this genus, but for the time being the ques- 

 tion must be left open. 



Spiny dogfish (Squalus acanthias Linnaeus), p. 44 



Jensen ("The Selachians of Greenland," in Mindeskrift for Jepetus Steen- 

 strup, 1914, p. 7) lists several definite records of this species from west Greenland, 

 where, however, it appears only as a stray from the south. We find no record of 

 it on the American coast north of the Straits of Belle Isle. 



Black dogfish (Centroscyllium fabricii Reinhardt), p. 52 



Jensen (" The Selachians of Greenland, " in Mindeskrift for Jepetus Steen- 

 strup, 1914, p. 4) lists several specimens from Davis Straits and from west Green- 

 land, where it seems rather common. He also reports cephalopods, crustaceans, 

 and Medusas from their stomachs, and remarks that the shark is viviparous, having 

 been taken gravid in February with embryos 124 millimeters long. 



Greenland shark (Somniosus microcephalus Bloch and Schneider), p. 53 



Jensen ("The Selachians of Greenland," in Mindeskrift for Jepetus Steen- 

 strup, 1914, p. 8) gives an interesting account of the habits of this shark in west 

 Greenland waters, and of the local shark fishery. 



Shad (Alosa sapidissima Wilson), p. 113 



Dr. A. H. Leim's report on his studies on the shad of the Bay of Fundy, carried 

 out under the auspices of the Biological Board of Canada (Contributions to Cana- 

 dian Biology, new series, 1924, vol. 2, part 1, pp. 163-184) contains much important 

 information on the life history of the species. Received too late for discussion in 



551 



