14 U.S. NATIONAL MUSEUM BULLETIN 236 



p. 482.— Sars, 1925, p. 346. — Pesta, 1927, p. 37.— Marine Biological Asso- 

 ciation, 1931, p. 157.— Rose, 1933, p. 247, fig. 312.— C. B. Wilson, 1936, p. 

 370.— Nicholls, 1944, pp. 10, 11.— Herbst, 1953, p. 266.— Marine Biological 

 Association, 1957, p. 160. — Noodt, 1958a, p. 156. 



Found on soft, muddy bottoms and on laminarians; occasionally, 

 especially during the night, in surface plankton. Though always in 

 small numbers, the species has been recorded from the west coast of 

 Ireland in Koundstone Bay and Bantry Bay (Brady and Robertson, 

 1873); the Plymouth region of England (Norman and T. Scott, 1906); 

 various localities in Scottish waters: the Firth of Clyde (Brady, 

 1878), the Fu-th of Forth (Brady, 1878; T. Scott, 1894a), and Moray 

 Firth (T. Scott, 1903). Moreover, it occurs along the north coast of 

 Norway near Kristiansund (Sars, 1902) and in northern Canadian 

 waters in the Bay of God's Mercy on Southampton Island (C. B. 

 Wilson, 1936). Additional records are from the Azores area in the 

 Atlantic (Sars, 1925), from Banyuls-sur-Mer, France, on the Medi- 

 terranean (Rose, 1924, 1933; Herbst, 1953), from the Indian Ocean 

 south of Socotra Island (Thompson and A. Scott, 1903), and in pearl 

 oyster washings from the Ceylon pearl oyster banks (Thompson and 

 A. Scott, 1903). The females measure about 0.8 mm.; the males, 0.7 

 mm. The distribution of this form, as evident in the records given 

 above, is wide, but because of its bottom-dweUing habit, it easily 

 escapes detection. 



Pseudocyclops umbricatus Giesbrecht, 1893 



Pseudocyclops uriibricatus Giesbrecht, 1893, p. 64, pi. 5 (figs. 16-31). — Giesbrecht 

 and Schmeil, 1898, p. 125.— Gurney, 1927, p. 455.— Brian, 1928, pp. 35-37.— 

 Nicholls, 1944, pp. 10, 11.— Gohar, 1954, p. 58.— Noodt, 1958a, p. 156.— 

 Bowman and Gonzdlez, 1961, p. 49. 



Found on sandy and muddy bottom in the Bay of Naples, Italy 

 (Giesbrecht, 1893; Brian, 1928); near Port Said, Egypt (Gurney, 

 1927); and in Lake Timsah on the Suez Canal (Gurney, 1927). It 

 has been found from a depth of some decimeters down to 120 m. 

 depth. The females measure 0.60-0.65 mm.; the males, 0.54 mm. 

 Both Giesbrecht and Gurney seem to have studied a fair number of 

 specimens; Brian studied 3 females. 



Pseudocyclops magnus Esterly, 1911 



Pseudocyclops magnus Esterly, 1911, p. 223, pi. 1 (figs. 6, 8), pi. 3 (fig. 23), pi. 4 

 (fig. 41).— Nicholls, 1944, p. 10.— Noodt, 1958a, p. 156.— M. S. Wilson, 

 1958, p. 178. 



In spite of Nicholls' arguments in favor of the synonymy of this 

 form with Pseudocyclops latens Gurney, I have left both forms separate. 

 There is a considerable discrepancy in size, whereas in P. magnus 

 the 4th and 5th thoracic somites are separate. Esterly's description 



