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8 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 20
wards and slightly into the mantle cavity. The anal siphon has smooth
edges in the species which have been studied. Below the contiguous part
and the septum there is a part, sometimes elongate like a siphon but open
ventrally, where the man™ edges may be furnished with tentacles or
papillae of varying shape, or may be smooth. This is the incurrent or
branchial part of the mantle opening (cfr. text-fig. 10).
In the present paper some anatomical characters which are easily seen
or which can easily be studied even in empty valves have been mentioned
for most of the species. The posterior part of the mantle margin is always
described and drawn from preserved animals and may vary slightljtllj^r
different specimens according to the degree of contraction. The major
features are, however, believed to be correctly shown in the drawings.
A thorough anatomical survey of the whole animal will certainl$jMB
needed before definite conclusions as to the relations of the various
supraspecific groups can be made.
Despite this weakness and certainly some wrong conclusions, it is hoped
that this study of a few mytilid species will clarify some questions and
be of help for future study.
NOMENCLATURE
The name of a species or a supraspecific group has only one purpose,
namely, to be referable to one well circumscribed uniffiof animals. A
scientist should know the supraspecific groups of his specialty so well
that on hearing the name of a species unknown to him, he can immediately visualize it by comparison with well known species of the same
group. If a supraspecific group is made very wide, however, and therefore vaguely circumscribed, the scientist has to know each species to
remember the characters peculiar to it.
By a strict application of the International Rules of Nomenclature,
many names, familiar for decades to scientists from some parts of the
world, have to be changed. This procedure is inconvenient for present
day scientists, but it will not be more difficult for future students than
the use today of papers one hundred years old. There have always been
different opinions about the scientific names and so numerous changes
have been made during the years. Certainly these changes are of no
benefit to systematics and taxonomy, and if they could be stopped by
fixing names to good descriptions and illustrations, with international
cooperation, it would be a great benefit to systematists and to zoologists
in all branches.
Object Description
Description
| Title | AHF-PUB-PE-20-01~020 |
| Format (imt) | image/tiff |
| Contributing entity | University of Southern California |
| Filename | AHF-PUB-PE-20-01~020.tiff |
| Full text | 8 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 20 wards and slightly into the mantle cavity. The anal siphon has smooth edges in the species which have been studied. Below the contiguous part and the septum there is a part, sometimes elongate like a siphon but open ventrally, where the man™ edges may be furnished with tentacles or papillae of varying shape, or may be smooth. This is the incurrent or branchial part of the mantle opening (cfr. text-fig. 10). In the present paper some anatomical characters which are easily seen or which can easily be studied even in empty valves have been mentioned for most of the species. The posterior part of the mantle margin is always described and drawn from preserved animals and may vary slightljtllj^r different specimens according to the degree of contraction. The major features are, however, believed to be correctly shown in the drawings. A thorough anatomical survey of the whole animal will certainl$jMB needed before definite conclusions as to the relations of the various supraspecific groups can be made. Despite this weakness and certainly some wrong conclusions, it is hoped that this study of a few mytilid species will clarify some questions and be of help for future study. NOMENCLATURE The name of a species or a supraspecific group has only one purpose, namely, to be referable to one well circumscribed uniffiof animals. A scientist should know the supraspecific groups of his specialty so well that on hearing the name of a species unknown to him, he can immediately visualize it by comparison with well known species of the same group. If a supraspecific group is made very wide, however, and therefore vaguely circumscribed, the scientist has to know each species to remember the characters peculiar to it. By a strict application of the International Rules of Nomenclature, many names, familiar for decades to scientists from some parts of the world, have to be changed. This procedure is inconvenient for present day scientists, but it will not be more difficult for future students than the use today of papers one hundred years old. There have always been different opinions about the scientific names and so numerous changes have been made during the years. Certainly these changes are of no benefit to systematics and taxonomy, and if they could be stopped by fixing names to good descriptions and illustrations, with international cooperation, it would be a great benefit to systematists and to zoologists in all branches. |
| Archival file | hancockunpub_Volume22/AHF-PUB-PE-20-01~020.tiff |
