COPEPODA FROM IFALUK ATOLL 191 



showing considerable range in setation, some species such as amblyops 

 having the number of setae approaching that of Amphiascopis, while 

 others show a reduced setation approaching the condition in the next 

 genus [Amphiascoides]" (1941b, p. 79). The following list shows 

 the species that NichoU's assigned to the genus Mesamphiascus and 

 their present designation: 



imus Bulbamphiascus inius (Brady, 1872) 



denticulatus Bulbamphiascus denticulatus (I. C. Thompson, 1893) 



blanchardi Typhlam-phiascus blanchardi (T. and A. Scott, 1893) 



erylhraeus Robertgurneya siviilis (A. Scott, 1896) 



confusus Typhlamphiascus confusus (T. Scott, 1902) 



simulans Robertgurneya similis (A. Scott, 1896) 



varians Arnphiascus varians (Norman and T. Scott, 1905) 



pacificus Arnphiascus pacificus G. O. Sars, 1905 



exiguus Haloschizopera exigua (G. O. Sars, 1906) 



parvus Arnphiascus parvus G. O. Sars, 1906 



propinquus Arnphiascus propinquus G. O. Sars, 1906 



sinuatus Arnphiascus sinuaius G. 0. Sars, 1906 



tenellus Arnphiascus tenellus G.O. Sars, 1906 



typhlops Typhlamphiascus typhlops G. O. Sars, 1906 



amblyops Arnphiascus amblyops G. O. Sars, 1911 



bulbifer Haloschizopera bulbifer (G. O. Sars, 1911) 



lageniroslris Rhyncholagena lagenirosiris (G. O. Sars, 1911) 



norniani Bulbamphiascus imus (Brady, 1872) 



typhloides Typhlamphiascus typhloides (G. O. Sars, 1911) 



spinifer Robertgurneya spinifer (Farran, 1913) 



angustipes Arnphiascus angustipes Gurney, 1927 



junodi Haloschizopera junodi (Monard, 1935a) 



mathoi Haloschizopera mathoi (Monard, 1935) 



salammboi Teissierella salammboi (Monard, 1935) 



gautheri Arnphiascus gautheri Monard, 1936 



In regard to the selection of a type for his genus Mesamphiascus, 

 Nicholls (1941b, p. 79) states: "It is, however, difficult to select a 

 type species, but perhaps parvus Sars (1906, p. 162, pi. clii) is suitable, 

 occupying a more or less central position in the genus, etc." It 

 appears, therefore, that the designation of a type for the genus is 

 ambiguous and, on this ground alone, the genus would have to be 

 rejected. The genus, moreover, in the sense of Nicholls, cannot be 

 maintained but would have to be restricted — an impossible task since 

 the definition is very vague: "... Arnphiascus having two and one 

 inner setae on the middle segments of the second and third endopods 

 respectively" (loc. cit.). 



Humes (1953, pp. 368, 371) has used the genus Mesamphiascus to 

 accommodate a new specices, described as M. ampuUifer, recovered from 

 the mouth parts of Homarus americanus Milne Edwards — a very 

 uncommon copepod habitat. I cannot endorse Humes' view. That 

 Humes experienced difficulties in his attempts to fit his new species 



