1897] 71 
CORRESPON DENCE 
OCEANIC ICHTHYOLOGY 
Tue reviewer of Goode and Bean’s ‘‘Oceanic Ichthyology” (Natural Science, vol. x., 
pp. 388-840) has made a gratuitous assumption, which devolves on me unmerited credit 
and responsibility. 
The reviewer says ‘‘it is to be noted that the literary part of the work bears signs 
of having been intrusted to a third author not under proper control of the two 
responsible authors.” The ‘‘ third author” is evidently myself. I feel compelled to 
deny either credit or responsibility for all that is not specifically accredited tome. Dr 
Goode devoted much time and thought to the keys, and I had nothing to do with the 
original compilation. 
The specific information that certain fishes have and others have not a mesocora- 
coid, so far as the italicised portions credited to me are concerned, I am responsible for, 
but not entirely for their application. 
The critic remarks, ‘‘as a matter of fact, the vast majority of the fishes placed 
here have not been examined with reference to this point.” True; but enough have 
been examined to authorise the deduction formulated. The same argument might be 
adduced against other generalisations. . . . 
As to the definition of Pterothrissidae, it will be evident from the context that the 
mistake is due to unintentional repetition instead of the requisite antithesis. The 
family Alepocephalidae is defined as having the ‘‘ dorsal fin similar and opposite anal,” 
and the Pterothrissidae should have been contrasted as having the dorsal fin unlike, 
and longer than anal. Undoubtedly carelessness and oversight are manifest, and I am 
willing to assume that I glanced over the proof and therefore to share the blame, but I 
had nothirg to do with the original manuscript. Drs Goode and Bean, as well as my- 
self, had much on hand, and doubtless the proof sheets were often read in a perfunctory 
manner. But in this respect, we have good company... . 
Such mistakes unfortunately are too common and are generally designated as 
‘*slips of the pen” or ‘‘ lapsus calami.” I do not defend them, but it does not become 
the guilty to animadvert on them too strongly. .. . 
What are or what are not family characters, is a question about which Dr Giinther 
and I have long differed, and I wish neither to defend my view nor to attack those of 
others on this occasion. All the many American naturalists, at least, agree with me on 
such points. Other strictures I leave to the surviving of the authors, if he should deem 
them worthy of attention, 
Some notice of the remarkable novelties obtained since the publication of the 
results of the Challenger Expedition might have been given by the reviewer, but I 
shall not trespass further on your space to do so. THEO. GILL. 
[We regret that Dr Gill should assume our review of Goode and Bean’s ‘‘ Oceanic 
Ichthyology ” to have been written or inspired by Dr Giinther, who had no share what- 
ever in its preparation. Like many unsigned reviews in Natural Science, it was the 
work of more than one author, and expressed the views of the editorial management of 
this journal, not those of any one individual. We have therefore omitted from Dr 
Gill’s lettter some remarks on Dr Giinther’s works.—Ep. Nat. Sci. ] 
SLUGS 
I HAVE recently received from an American malacologist a communication, in which 
he says that in a paper,* written in conjunction with Lieut.-Col. H. H. Godwin-Austen, 
I have ‘‘ wrongly applied the term slug by using it for such genera as Parmarion, 
Microparmarion, &e.” 
It is very largely a question of individual opinion as to what genera should be 
included under this term, but I fail to see any reason why Parmarion and its allies 
should not be termed slugs. 
The slugs are not a group by themselves which can be separated into distinct 
families apart from the rest of the Pulmonata. On the other hand, very many genera 
are closely related to genera in which there is a conspicuous shell. In the above- 
mentioned paper the same opinion was expressed as follows :—‘‘ We think that future 
* Proc. Zool, Soc., 1895, p. 249, 
