267 
not necessarily give their names to the species which the include. 
Thus they discourage the growth of synonyms, offer no awkward 
bars to the free passage of any species from one group lo nearer 
le lati ves, and at the same time lessen the confusion which the 
present unsettled state of opinion regarding the relationships of 
existing species tends to produce.’ When the groups are to take 
the places of genera, one should believe that the generic names 
must be quite superfluous except as synonyms, and I am at a loss 
to undeistand in what manner this retention of them niay be able 
to diminish the growth of synonyms or to lessen confusion of any 
kind, as I am much more inclined to think that this method would 
have quite the opposite result. 
In the year 1904 Professor C. C. Nu ttin g., Iowa, published 
a most valuable work on the American Sertulariidae, in which as 
a result of his systematic investigations into this family he sets 
foith the asseition that the characters taken from the operculum 
and the hydrothecal margin are insufficient in themselves to furnish 
a base foi the classification of the Sertulariidae *), though he 
„thinks them most important aids in defining’ certain genera” and, 
besides, he quotes parts of an unpublished manuscript on the 
structure of the operculum written by Mr. J. H. Paarman 2 ). 
according to which the representation the present author has given 
of the operculum in the Sertulariidae is incorrect. I am first to 
treat the latter point, and the following representation of the 
lesults to which the two authors have arrived chiefly refers to Ser- 
tularia pumila. 
According to the named authors the hydrothecal. margin is 
provided with two lateral teeth, between which there are stretched 
two quite homologous membranes of unequal size, the abcauline 
being considerably larger than the adcauline one. They form 
together the side-walls of an A-tent, the front and rear of the 
tent being closed by the two opposite hydrothecal teeth, and there- 
9 44, p. 41. 
2 ) 44, pp. 20, 40. 
