480 Correspondence—Dr. F. L. Kitchin. 
name to any portion of it at his discretion,” etc. In the present 
instance, however, Professor Gregory did select the genotype, but had 
the conception that the arm-structure was similar to the accompanying 
form, leptosoma. Since, therefore, the genotype was selected in error, 
it is necessary to follow an unwritten, but nevertheless, patent rule, re- 
forming the genus thus broken up, and instituting the only remaining 
form—regarded as congeneric, be it remembered, by Gregory—as the 
valid claimant. The Stricklandian rule quoted above should afford 
sufficient authority and reason for such procedure, otherwise rules of 
nomenclature, made with the best intent, may easily prove a 
stumbling - block to scientific progress, and a cause of confusion, 
instead of a simplifying of scientific terminology. 
In the interpretation of the lateral ossicles in the two species of 
Sturtzura, it may be more convenient to regard the curved, fusiform 
ossicles as an intermediate series—derived from a boot-shaped ambu- 
lacral, but now perfectly distinct—and to still refer to the spine- 
bearing plate, as Dr. Bather suggests, as the adambulacrals. In fact, 
there seems a transitional tendency shown in these forms, from the 
typical Protasterid towards a Lapworthurid, especially as there is some 
indication of the ventral arm-ossicles tending to become parallel on the 
distal and proximal margins. 
Dr. Bather’s suggestion that Sturtzwra can lapse and be resuscitated 
under a fresh diagnosis with S. drisingoides and another species is 
surely untenable? As the original genotype is now shown to be a form 
of Protaster, this action would be condemned by the rule adopted by 
many zoologists of ‘‘once a synonym always a synonym” as applying 
to generic terms. 
The last paragraph of Dr. Bather’s excellent and suggestive review 
needs no comment, for no one responsible for museum arrangement 
would seriously entertain the idea of translating into free English 
every scientific term on the exhibited labels. 
F. CHApMan. 
NationaL Museum, MrLBourRne. 
August 21st, 1907. 
A CORRECTION. 
Srr,—In my paper ‘‘Notes on the Invertebrate Fauna of the 
Uitenhage Series in Cape Colony,” published in the present volume of 
the GroroercaL Maeazine, July number, pp. 289-295, an inaccurate 
statement was inadvertently allowed to pass into print. With 
reference to an assemblage of fossils mentioned on p. 290, the 
following sentence occurs, commencing on line 21 from the top of 
the page: ‘‘All these, so far as we know, are confined elsewhere to 
the Cretaceous rocks . . . .” This statement should not, of 
course, refer to the genus Solecurtus, and the sentence should read as 
follows: ‘‘ All these, with the exception of Solecurtus, are, so far as 
we know, confined elsewhere to the Cretaceous rocks . . . we 
I hope you will be able to give publicity to the correction of this 
oversight. F, L. Kireniy. 
