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Full text of "Armature of helicoid landshells"

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88 



SCIENCE-GOSSIP. ^^^^ 



ARMATURE OF HELICOID LANDSHELLS ; 

And a New Species of Gorilla. 
By G. K. Gude, F.Z.S. 



' I "HAT Mollusca have numerous enemies is a 
fact well known to naturalists, for not only 
do they serve as food for many mammals, birds 
and reptiles, but they are preyed upon by some 
insects, and even by other mollusca. Naked slugs 
are especially exposed to the attacks of birds, slow- 
worms and snail-slugs (Testacella) ; and, in foreign 
countries, of carnivorous snails, such as Glandina 
and others. Shell-bearing Mollusca likewise are 
devoured by birds and mammals ; they have 
besides many insect enemies, particularly under 
tropical climates, and we shall, therefore, not be 
surprised to find that in several instances tliese 
creatures have come to be provided with special 
means of protection. This has been attained in 
various ways, indirectly by protective resemblance 
between the forms or colours of the shells and 
their immediate surroundings ; or, directly, by 
special structures, such as teeth, plates, or constric- 
tions, serving as buttresses or barricades behind 
which the animal can withdraw. It is probable, 
however, that these structures may at the same 
time help to strengthen and support the outer wall 
of the shell, and in this manner safeguard the 
mollusc against injuries, accidental or otherwise. 

In the following notes I propose to consider the 
several special structures or forms of armature, 
just indicated, as they are found in many of the 
genera of Helicidae, which have come under my 
.notice. It will, of course, be understood that the 
operculum, which is so generally present in marine 
mollusca, and in the land and freshwater shells 
taxonomically associated with them, and the 
clausilium or elastic door, which characterizes and 
gives its name to the well-known genus of land- 



shells Clavsilia, are also means of protection ; but 
they do not form an integral part of the shell, and 
I do not propose to consider them here. A point 
to be noticed with regard to the armatures under 
consideration is that they are not the exclusive 
property of any particular genus, or wider group, 
but occur in various genera or groups, often of 
distant affinity. 

I. Gorilla. 

The Helicoid genus Corilla, with which we are 
concerned in the first place, is an interesting group 
of landshells inhabiting the jungles of Ceylon, 
with a single outlying species in the southern 
point of the Indian Peninsula. The armature, 
which sometimes exhibits considerable complica- 
tion, consists generally of a variable number of 
revolving plates or folds on the inner side of the 
shell - wall. It may be 
mentioned as a curious 
fact that a single species, 
namely Corilla chai'pcn- 
tieri (Geylon), is devoid 
of armature (fig. i). 

I was favoured not 
long ago by Mrs. R. S. 
Fry, of Singapore, with 
some shells collected by 

her during a stay of several months in Ceylon ; 
amongst these were eight specimens of a shell which, 
at first, I was inclined to refer to Corilla odontophora, 
of Benson, but, after some research and careful 
comparison with allied forms, it became evident 
that I had to deal with a new form. It is probable, 
however, that it already exists in collections, as 
Mr. Hugh Fulton sent me a specimen labelled 




Fig, I.— Corilla clunpentioi. 



SCIENCE-GOSSIP. 



89 



Corilla hunibcrti, and Mr. John Ponsonby also 
possesses specimens of a similar form under the 
same name ; but on submitting one of my specimens 
to the describer of that species, Dr. A. Brot, 
of Geneva, he informed me at once that it was 
not Corilla humberti, but rather, he thought, a 
variety of Corilla erronea, of Albers. Dr. Brot 
obligingly forwarded one of the only two speci- 
mens of Corilla humberti known to exist in collec- 
tions, so that, thanks to his kindness, I am 
enabled to give a figure of it for comparison with 
its allies. 

There appears to be a certain amount of 
confusion with regard to the limits of some 
species, as well as to the position and number of 
teeth or plates in some of the Cingalese members 
of the genus, and it is hoped that the present 
notes may help to elucidate some of the doubtful 
points. The new shell is certainly distinct from 
all the published species of the group, and I have 



Several of the specimens being more or less 
weatherworn, I had the less compunction in break- 
ing away parts of the walls at various points, so as 
to examine their internal structure thoroughly, and 
to report thereon with precision. To enable the 
reader to understand the following remarks, I will 
here mention that those teeth or plates found on 
the inner wall of the shell are known as parietal, 
while those on the outer wall are called palatal. 









Fig. 2. — Corilla fryae. Fig. 3. — Corilla erronea. 

much pleasure in associating with it the name of 
the lady to whose kindness I am indebted for this 
valuable addition to my collection.* 

* Corilla fryae, n. sp.- — Testa late umbilicata, ovato-rotun- 
data, discoidea, iolidula, rufo-castanea, planulata, oblique 
costulata, subtus valde concava, striata, pernitida ; spira 
plana, sutura vix impressa. Anfr. 5 vix convexiusculi, inter 
suturam et peripheriam valde angulati, ultimus subtus 
ornatur striis spiralibus quae secundum latus lineis vel rugis 
impressis obliquis decussantur; antice convexior, valde 
dilatatus, profunda descendens. Apertura obliqua, obtuse 
subcordata, lamellis 3 parietales (media elongata, validaque, 
laterales minores, profundaeque). 4 palatales flexuosae, 
longulae, perlucentes, 3 ab apertura visibiles. Peristoma ex 
albido purpurescens vel rufo-castaneus, callosum valde 
reflexum, marge superior sub-dentate crassior, inferior dente 
valido atquae quadrate armatur. — Diam. maj. 26, min. 20, 
alt. 8 mm. Hab. — Albion Estate, Lindula District, Ceylon. 

Corilla fryae differs from Corilla erronea (compare figs. 311 
and 36) in being more rounded in outline, larger, darker in 
colour and more shining beneath, the ribs are more regular 
and less coarse ; the whorls are less convex, almost flattened 
and distinctly angulated, almost keeled, midway between the 
suture and the periphery, while the suture is less impressed ; 
the last whorl is more constricted, and suddenly widens 
towards the aperture, becoming again constricted behind the 
peristome, and it is more deeply deflected in front ; the 
mouth is much less oblique, the palatal folds are longer and 



Fig. 4. — Corilla fryae. 

In fig. 4<j, the parietal plates are shown on the 
left and the palatal on the right of the aperture ; 
the figure shows a perfect shell of Corilla fryae. 
To the left of the aperture the median plate will be 
observed reaching outwardly up to the extreme 
margin of the parietal callus, while the tips only of 
two other plates, one on each side of the median, 
can be discerned. I propose to designate them by 
numerals, and, beginning at the top of the shell, 
the first will of course be No. i, the median No. 2, 
and the next No. 3, In fig. 46, a part of the 
outer wall has been removed, and the edge thus 
exposed is shown perpendicularly to the line of 
sight ; here on the right the curved and revolving 
parietal plates Nos. i and 3 show their inner 
terminations, while a reference to fig. ^e will 
explain why parietal plate No. 2 is invisible in the 
former figure, as it terminates at about half the 
length of Nos. i and 3, and there unites with the 
former. To return to fig. 4^, on the left four 
palatal plates will be observed, which will be 
numbered i, 2, 3 and 4 respectively, from the top 
of the shell downward. 

It will be noticed that No. i curves upwards 
towards the shell-mouth (not shown in the figure), 
while No. 2 interlocks between the parietal teeth 
Nos. I and 3, and as it curves upwards towards the 

more flexuous, and the tooth on the basal edge of the peris- 
tome is longer and more quadrate ; in this latter respect, as 
well as in contour and shape, the new shell more resembles 
Corilla odontophora. The specimens were all collected on 
the edge of a jungle where a new clearing was being made, 
on the Albion Estate, Lindula District, Ceylon (figs. 2, 4, 5, 6). 



go 



SCIENCE-GOSSIP. 



mouth, following for some distance the curvature 
of the second parietal plate, it is almost in 
juxtaposition with the latter ; the third palatal 
plate also curving upwards, terminates below the 
third parietal one which curves downwards, and 
they therefore cross each other about the middle ; 
No. 4 is situated very low down, close to the 
junction of the outer with the inner wall, and 
proceeds in an almost horizontal direction. These 
palatal plates are distinctly visible externally 
through the shell, and they are thus shown in 
figs. 4c and ^d, the latter figure exhibiting Nos. 
I, 2 and 3, while the former shows Nos. 2, 3 and 4. 
The specimens delineated in figs. 2 and 4 are all 
mature, and as in this condition they are composed 
of 5 whorls, it follows that the plates are placed 
near the end of the fifth whorl. In fig. 4/ the 
palatal plate No. 2 is shown by itself, the upper 
convex line indicating its attachment to the shell- 
wall. An interesting fact was revealed by the 
examination of an immature specimen received 
with the others ; on breaking away the walls at 
various points, five palatal plates were observed in 
the fourth whorl, at a point which would be inter- 
sected by a line from the apex of the shell to the 



and laminae of the Pupidae, observed that "they 
may answer the purpose of an operculum to keep 
out enemies, while they afford no obstacle to the 
motions of the soft and yielding body of the 
animal " (" Zoological Journal," iv., 1829, p. 168, 
footnote). As illustrating the vulnerability of 
unarmed shells, it may be mentioned that Jeffreys 
found a half-grown specimen of Helix strigella 
containing the larvae-form pupa of Drilus flavescens, 
the female of which has been named Cochleoctonus 
vorax from its snail-eating habit. He also found 
a similar pupa in a Helix incarnata, which, as in the 
case of Helix strigella, completely occupied the spire 
of the shell, of which it had devoured the former 
inhabitant (" Annals and Magazine of Natural 
History" (3), vi, i860, p. 348). Of much interest 
is a note by Lt.-Col. Godwin Austen, who, in a 
paper on the Asiatic landshell genus Pledopylis, 
states that "when breaking up a number of shells 
to expose the barriers and ascertain if their char- 
acters were constant, I was greatly interested to 
find in two instances the presence of small insects 
that had become fixed between the teeth." He 
further remarks that those shells possessing such 
bars to the predatory visits of insects, such as 






Figs. 5 and 6. — Corilla fryae, immature x 2. 



Fig. 7. — Corilla envnea. 



point where the plates would be found in the mature 
shells, This specimen is represented in figs. 5 
and 6. On reference to fig. 5 it will be seen 
that the upper four of these plates are much 
broader than those of the mature shells, as they 
reach nearly to the inner wall and overlap, 
being placed close together, slanting upwards, but 
scarcely curving ; No. 5 is very short and narrow, 
and corresponds in position to No. 4 in the older 
shells ; fig. 6 shows the upper four plates in their 
immature position as seen through the shell. No 
plates being found in the fourth whorl of the 
mature shells, the inference is that as the shell is 
completed the plates first formed are absorbed by 
the animal, and this fact supports the view that 
the plates form barriers to exclude predatory 
insects. It may also be assumed that the animal 
produces similar plates from an early stage of its 
existence, absorbing them as each successive 
whorl with its complement of plates is completed ; 
but this of course can only be demonstrated by the 
examination of a series of shells in various stages 
of growth. That structures of this kind serve as a 
means of defence was suggested as long ago as 
1829 by Guilding, who, in speaking of the teeth 



certain kinds of beetles, ants, or even leeches, all 
of which swarm in the forests where the shells 
are found, would have the best chance of sur- 
viving. ("Proceedings of the Zoological Society 
of London," 1874, P- 611.) 

In fig. yb, a portion of the inner side of the 
outer wall of the allied species, Corilla evronea 
(Ceylon), is shown with the plates in situ, disposed 
in much the same manner as in Corilla fryae ; they 
are, however, shorter and less curved ; the parietal 
plates are almost identical in position and shape 
with those of Corilla fryae, as shown in fig. ya, but 
they are shorter and the union of Nos. i and 2 is 
not so complete. Fig. jc shows a specimen side- 
ways, which is of interest on account of a small 
adventitious tooth between palatal plates Nos. 2 
and 3. 

In figs. 8a and Sb Corilla rivolii, of Deshayes 
(Ceylon), is delineated, the latter figure showing 
the remarkably reflected lip, and the three parietal 
plates, of which Nos. i and 3 are much more 
exserted than in the two previously-mentioned 
species ; the palatal plates also reach much nearer 
to the edge of the lip than in the other two species, 
but they are not shown in the figure, as the mouth 



SCIENCE-GOSSIP. 



91 



of the shell was turned too far to the left. Fig. 8a 
shows the same shell with part of the outer wall 
removed, from which it will be seen that the 
arrangement of the plates is similar to that in 
Gorilla fryae and C. erronea ; there is, however, 
what appears to be a small adventitious palatal 
plate or tooth between Nos. 3 and 4, but this 
was not found to be constant in other specimens 
of this species which I examined, and it may 
therefore be assumed that this is an abnormal case. 
Since writing the above, Mr. Ponsonby has kindly 

placed at my disposal two 
immature specimens of 
C. rivolii, the examination 
of which bears out the 
statement already made, 
that plates are formed at 
the various stages of 
growth, which are after- 
wards absorbed. These 
two specimens are shown 
in figs, ga-gf, of which 
a-e exhibit one with four 
whorls completed, having five palatal plates, which 
resemble those of Gorilla fryae (figs. 5 and 6) in 
being different in character from the mature plates. 
Here again they are much broader, they are also 
seen to be triangular, to overlap and to reach 
almost to the inner wall ; no parietal plates are 
present. In fig. ga the palatal plates are shown 
as seen on looking into the aperture, in fig. gb 
they are looked at more from below, the shell 
being tilted a little. In figs, gc and gd they are 
shown as seen externally through the shell- 
wall. In fig. ge the same specimen is depicted, 
seen from above, the dagger indicating the place 




Fie. 8. — Corilla rivolii. 





h %. 



d 
Fig. 9. — Corilla rivolii immature. 

where the plates are found. Fig. g/ shows another 
immature specimen, the dagger here also indicating 
the position of the plates ; but while in the former 
specimen they are placed at the end of the fourth 
whorl, they are here found at a place where only 
three and-a-half whorls have been completed. 
Lt.-Col. H. H. Godwin Austen, in a letter, 
confirms my surmise as to the temporary character 
of these plates, stating that those found in the old 
shells differ very much from what those found in 



the young might be supposed to develop into. He 
thinks that the early folds are absorbed to make 
way for subsequent ones. As will be seen from the 
consideration of Gorilla odontophora further on, 
however, this is not always the case, since in one 
mature specimen I have found the immature 
palatal folds still existing. 

Gorilla odontophora does not seem to be well 
understood, and the figure given in Tryon's 
"Manual of Conchology " (2), iii., t. 33, f. 34, 
copied from Hanley and Theobald's " Conchologia 
Indica," t. 57, f. 6, is somewhat misleading, as it 
evidently represents an immature specimen, show- 
ing the palatal folds as they appear from the 
aperture, but no reference is made to this fact. 
Mr. Ponsonby having in his possession two mature 
specimens, which he doubtfully referred to this 
species, kindly permitted me to open one, which is 
shown in figs. loa — lot^. On reference to fig. lob it 








Fig. 10. — Corilla odontophora. 

will be seen that only two parietal folds are 
present, corresponding to Nos. 2 and 3 in the 
previous species. Fig. loc exhibits the plates as seen 
from behind their inner terminations, and it will be 
observed that there are four palatal folds, the 
upper three of which are shown through the wall 
of the shell in figs, lod and lo^, while fig. loa shows 
the entire shell from below (restored), with plates 
Nos. 3 and 4 showing through. On comparison 
with the figures of Gorilla erronea and Gorilla fryae, 
it is seen that in Gorilla odontophora the palatal 
folds are much shorter and less flexuous than in 
the two former, and, as correctly stated by Benson 
in describing this species ("Annals and Magazine of 
Natural History " (7). xvi, 1865, p. 175), they "are 
entirely visible from the aperture." Another point 
to be noted is that the outer terminations (i.e. nearest 
the aperture) of the upper three palatal folds form 
an oblique line parallel with the peristome, Ibe first 
one being nearest the aperture, while in GcHHa 



92 



SCIENCE-GOSSIP. 



erronea and Gorilla fryae they form a semicircle, the 
second fold being nearest the aperture. The shell 
of Gorilla odontophora is more regularly and less 
coarsely ribbed than that of Gorilla erronea, and 
larger, although composed of only 4-4^ whorls, 
while the other two species have 5 whorls ; it 
differs further from Gorilla erronea in that the last 
whorl is more deflected in front, more 
tumid, and then suddenly contracted 
behind the peristome, more resem- 
bling Gorilla fryae in these respects, as 
also in the presence of a quadrate 
tooth on the basal margin of the 
peristome. Before concluding the 
consideration of this species, I would 
draw attention to fig. loa, in which, 
though the shell is adult, is seen 
the immature form of palatal folds 
immediately behind the callus of the mouth, and, 
-as already mentioned, a circumstance which shows 
that the earlier folds are not invariably absorbed 
■on the completion of the shell. 

Gorilla humberti, also Cingalese, is extremely rare 
in collections. As Benson, in the paper cited above, 
throws some doubt on the correctness of Dr. 
Brot's figure of this species in the "Journal de 
Conchyliologie," xii., 1864, t. 2, f. 6, I was pleased 
to be able to give a new figure of it, and I am in a 




Fig. II. — Ccrilla humberti 



position to confirm Benson's conjecture that the 
original figure is slightly misleading, as the basal 
palatal fold appears to be joined to the suture 
owing to the position in which the specimen was 
placed, but on tilting the shell from the left side 
the fold is plainly seen to be unconnected with the 
suture, and it is thus shown in my fig. 11 ; this fold 
corresponds in position with No. 4 of 
the other species, while the parietal 
fold corresponds with No. 2 of the 
others. The specimen having been 
completely cut in half through the 
median plane, a close examination 
of the parietal fold reveals a slight 
fracture, and the inference forces 
itself upon my mind that, probably, 
in the process of cutting, it was 
partly cut away, and that it reached 
further back than it now appears. This form 
differs from the species already considered in 
having only one palatal and one parietal fold ; 
it is also decidedly more rounded in outline, but 
like Gorilla odontophora and Gorilla fryae, it has a 
quadrate, but less elongate, tooth on the basal 
margin of the peristome. 

The other species of Gorilla will be considered in 
a future communication, 

[To be continued.) 



126 



SCIENCE-GOSSIP, 



ARMATURE OF HELICOID LANDSHELLS. 
By G. K. Gude, F.Z.S. 

(Contiimed from page 92.) 



TN my last article, in speaking of Gorilla humberti, 
I stated that only two specimens were known 
to me to exist in collections, and that these were 
in the possession of Dr. Brot, who described the 
shell. Since writing, however, Mr. Ponsonby has 
shown me a specimen, which, upon being opened, 
proved to pertain to that species, although it is 
considerably less rounded in outline. The palatal 
tooth corresponds in size and position to that 
in Dr. Brot's shells, but the parietal fold extends 
much further back, a fact which confirms my 
surmise that this fold in the shell figured by 
Dr. Brot (and by me, fig. 11, ante p. 92) had 
been damaged in the 
cutting process. Colonel 
Beddome has informed 
me that he possesses 
three specimens of this 
species, which he has 
obligingly sent to me 
for inspection ; one of 
these agrees with Mr. 
Ponsonby's shell in 
being somewhat oblong, 
while the other two 
conform to Dr. Brot's 
types as regards outline. 
The species certainly 
appears to be less rare 

than was at first supposed, and it may turn up in 
other collections. 

We have now dealt with Gorilla cliarpentieri, C. 
fryae, C. erronea, C. rivolii, C. odontophora, and C. 
humberti. The only other species of the genus at 
present known, are C. anax, Benson, and C. bed- 
domeae, Hanley. 

The two species last named, with which we are 
here concerned, form a separate group in the genus, 
and, from considerations which will be explained 
further on, may be looked upon as being the oldest 
members of the group provided with plates. Gorilla 
cliarpentieri being the primordial form. This group 
of Gorilla anax (including C. beddomeae), is of equal 
value to the group of Gorilla erronea (including G. 
fryae, G. rivolii, G. odontophora and C. humberti) and 
to the remaining group of Gorilla charpentieri. 

Gorilla anax is shown in figs, iza-e, the 
drawings having been made from a specimen in 
Mr. Ponsonby's collection. It is the only species 
of Gorilla known to occur outside Ceylon, being 
found, as already stated, in the southern part of 
India. It is of a dark chocolate colour, and 
possesses three parietal and four palatal plates. 




Fig. 12. — Gorilla anax. 



Fig. 12a shows the entire shell, four of the plates, 
two parietal and two palatal, being visible from 
the aperture. The parietal plates are much 
broader than in the other species. No. i curves 
upwards, while No. 2 reaches as far as the 
parietal callus ; but, unlike those of the other 
species, they are separate.- No. 3 parietal plate is 
almost horizontal, with but a slight curve, as will 
be seen on reference to fig. 12c, the specimen 
being there figured with the outer wall removed. 
Fig. i2d shows the same shell with part of the 
outer wall broken away, and the plates are shown 
as they appear from behind their inner termina- 
tions. The palatal 
plates also are seen to 
be much broader than 
in the other species, and 
the three upper ones 
are much more oblique, 
resembling in this re- 
spect the immature 
plates found by me in 
three of the other 
species. In fig. lie a 
portion of the last whorl 
is drawn, in which the 
palatal plates Nos. i, 2 
and 3 are shown as 
they appear through 
the shell, while fig. 12& shows the entire shell from 
below with palatal plates Nos. 3 and 4 shining 
through. Colonel Beddome has been so good as to 
lend me several adult examples of this species for 
examination, one of which is of interest from the 
fact that it exhibits, in addition to the mature arma- 
ture, immature plates which are identical in form 
and position with those I found in an adult shell 
of Gorilla odontophora, and described in my previous 
article (ante p. 92). With these adult examples 
was an immature shell with three whorls com- 
pleted, which is specially noteworthy in that it 
possesses two sets of immature plates, one near the 
end of the third whorl, and the other a little beyond 
the place where two and a-half whorls have been 
completed. It may therefore safely be inferred that 
the plates are not absorbed till after completion of 
the new ones, and it will be remembered that this is 
not an isolated case, for, as already stated, two sets of 
plates were observed by me in a full-grown speci- 
men of Gorilla odontophora, and Colonel Beddome 
lent me a shell of this last-named species, identical 
in this respect. Colonel Beddome informs me 
that he collected his specimens of Gorilla anax on 



October, 1896. — No. 29, Vol. 3. 



SCIENCE-GOSSIP. 



12 J 



the Anamali Hills, in the Coimbatore District of 
South India, in moist woods, at 2,000 feet elevation, 
where it was very abundant on and under dead logs. 
Gorilla beddomeae (figs. 13 and J^a-s), is, I be- 
lieve, somewhat rare in collections. Mr. Pilsbry 
has not included it in his synopsis of Corilla 
(" Manual of Conchology," ix., p. 147), but, guided 
probably by its external characters, he refers 
it to the genus Plectopylis (see Errata, Index, 
p. 121, of the same work). The absence of 






Corilla beildoineae, type. 



vertical or transverse barriers on the parietal 
wall, however, amply warrants its inclusion in the 
present genus. The species differs in appearance 
from the others in being wrinkled, thinner in 
texture and much flattened above. Fig. 13 shows 
the type from Haycock Mountain, Ceylon, the 
specimen being in Colonel Beddome's collection. 
It will be noted that it is strongly and regularly 
wrinkled, the rugae being particularly. coarse above 
and about the keel, gradually decreasing towards the 
base. The specimen measures twenty millimetres in 
diameter. In figs, i^a-e a small variety from Wata- 
wala, Ceylon, is shown from a specimen kindly lent 
by Mr. Ponsonby, who, with his usual courtesy, 



Fia 




Corilla beddomeae, small variety. 



allowed me to open the shell, although it was his 
only specimen. It will be noticed that this variety 
is less coarsely wrinkled than the type ; it is also 
paler and smaller, measuring only sixteen millimetres 
in diameter. Fig 14^, which shows the shell with 
the outer wall broken away, discloses the fact that 
only two parietal plates are present, corresponding 
to Nos. 2 and 3 in those species possessing three 
plates ; for the sake of uniformity they will be 
numbered 2 and 3 ; both are visible from the aper- 



ture (see fig. 14Z)). No. 2 reaches to the parietal 
callus, and, as will be observed, it is long and irregu- 
larly flexuous, while No. 3 is very short. Of the four 
palatal plates Nos. i and 2 only are visible from the 
aperture. Nos. i, 2 and 3, are broad, and ascend 
obliquely, parallel to each other, while No. 4 is 
smaller, narrower, and revolves horizontally, paral- 
lel to the suture, as may be seen on reference to 
fig. i4f, which shows plates Nos. i, 2 and 3 shining 
through, and fig. i^d, which shows Nos. 2, 3 and 4. 
Fig. 14a shows all six 
plates from behind their 
inner terminations. 




Fig. 15. — Corilla charpentieri, 
var. hinidunensis. 



Colonel Beddome has 
also favoured me with 
the loan of specimens of 
a shell sent out by Mr. H. 
Nevill, under the name 
of Corilla Iwiidiuiensis, and 

published by him without description in " Enume- 
ratio Heliceorum et Pneumonopomorum insulae 
Ceylon adhuc detectorum " (1871), p. i. Mr. 
Pilsbry, in figuring this form in the ninth volume 
of the "Manual of Conchology," p. 148, t. 41, 
ff. 23-25, has, with his usual discrimination, reduced 
it to a variety of Corilla charpentieri, Pfeiffer, and a 
careful comparison of the two forms has convinced 
me that this view is the correct one, as the 
only difference which could be detected is that 
of size, Corilla charpentieri measuring twenty- 
nine millimetres, and Nevill's Corilla hinidunensis 
twenty-two millimetres. To complete the series 
I have thought it useful to add a figure of 







Fig. 16. — Corilla crronea, var. erronclla. 

this shell (fig. 15), which must now be known as 
Corilla charpentieri, var. hinidunensis. 

Since dealing with the group of Corilla erronea, 
Colonel Beddome has communicated to me 
another form, known only by the unique specimen 
which he received under the manuscript name of 
Helix erronella, Nevill (Ceylon). As manuscript 
names are a source of great trouble, I am pleased 
to have the opportunity of studying and figuring 



128 



SCIENCE-GOSSIP. 



this form (figs. i6 a-d). On comparing it with 
Corilla erronea, it is at once noticeable that it has 
great affinity with that species ; it is, in all 
probability, only a well-marked variety of it, and 
as it is known only from the single specimen it 
would certainly be imprudent to accord it higher 
than varietal rank. It possesses the same number 
of plates, but the shell is much smaller and 
thinner, and the palatal plates are much shorter 
and placed much nearer the mouth of the 
shell. The outer terminations of the parietal 
plates and the whole of the three upper palatal 
plates are visible from the aperture (see fig. i6a) ; 
palatal plate No. 3, which in Corilla erronea is 
nearly horizontal, is here strongly oblique and 
ascending, while No. 4 reaches nearly to the 
peristome (see fig. 16c). The form must be known 
provisionally as Corilla erronea, var. erronella. 

All the known forms of Corilla fall naturally into 




Diagram of Relationship of Corilla. 

the three groups of C. charpentieri, C. anax and C. 
erronea, already indicated. The first group, that of 
Corilla charpentieri (including the var. hinidunen- 
sis), is without internal plates ; the second, that of 
Corilla anax (including the two forms of C. 
beddomcae), has oblique palatal plates ; and the 
third, that of Corilla erronea (including the rest of 
the genus), has horizontal palatal plates. It will 
be remembered that the structure of the armature 
in young shells differs in a remarkable degree from 
that found in full-grown specimens. I have 
pointed out that in the former case the plates are 
invariably broad and obliquely slanting upwards 
(see ante pp. go and 91), while in the latter case they 
are, in some species at least, narrow and horizontal. 
From what we know of the retention of ancestral 
characters in young individuals , as explained by 
Mr. Darwin (" Origin of Species," sixth edition, 
p. 388), it may safely be assumed that the 
immature form of plates found in the young shells 



represents the form of plates which were possessed 
by the progenitors from which the existing armed 
members of the genus have sprung. Consequently, 
those species which have to some extent retained 
such characters in the adult state (i.e. Corilla anax 
and C. heddomeae) are the older forms ; while those 
species which diverged most in the adult state 
[i.e. the group of Corilla erronea) are of more 
recent origin. Assuming that the prototype which 
gave rise to the armed forms was devoid of arma- 
ture, the Corilla charpentieri group would represent 
the oldest forms of all, while Corilla beddomeae and 
C. anax would come next in the line of descent in 
one direction ; C. htimberti still later, but in another 
direction ; next C. odontophora, C. erronea and C. 
rivolii would appear to have branched off in 
separate directions ; and lastly, C. erronella and C 
fryae have diverged from the common stock. As it 
is extremely difficult to indicate the true relation- 
ship between any given group of species in a linear 
arrangement, I have attempted to overcome this 
difficulty in the accompanying diagram. It will, 
of course, be understood that this has reference to 
conchological characters only. 

I append a key to the species of Corilla which I 
venture to hope will prove serviceable : 

A. Shell without internal folds. . 

a. Shell large, diameter 29 mm. charpentieri. 

b. Shell smaller, diameter 22 mm. 

v. hinidunensis . 

B. Shell with internal folds. 

a. Palatal folds oblique. 

o. Two parietal folds .... beddomeae. 
p. Three parietal folds anax. 

b. Palatal folds horizontal. 

a. One parietal fold himbcrti. 

$. Two parietal folds .... odontophora. 
y. Three parietal folds. 

* Shell elliptic, palatal folds short, 
second scarcely curved. 

t Lip much reflected rivolii. 

tt Lip little reflected. 

1. Third palatal fold, 

almost horizontal . . erronea. 

2. Folds very short, nearer 

aperture, third palatal fold 
very oblique, ascending 

V. erronella. 
** Shell rounded, palatal 

folds longer, second 
much curved ... fryae. 
In concluding the consideration of the genus 
Corilla, I take the opportunity of expressing my 
grateful thanks to Mr. John Ponsonby, Colonel 
Beddome and Dr. Brot, for their kind and liberal 
assistance with specimens and information, and 
to Lieut. -Colonel Godwin-Austin for valuable 
information and suggestions. 

{To be continued.) 



154 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS. 

Bv G. K. GuDE, F.Z.S. 

{Continued from page 128.) 



II. Plectopylis. 
T N the genus Plectopylis, now to be considered, we 
find the armature more complicated than in 
Corilla. In the latter, we have seen the parietal 
plates to be invariably more or less horizontal, 
and the palatal plates — normally four in number — 
to be either horizontal or oblique, and always 
simple. The species of Plectopylis, however, are 
characterized by the possession of vertical as well 
as horizontal barriers, which in some cases are 
double, frequently bifurcate or ramified, and the 
plates or folds are often very numerous. The genus 
contains a far greater number of species than 
Corilla (more than fifty being known), and it has a 
much wider range, being found over the whole of 
the Indian Peninsula, including the Himalayan 
Range, Burma, Cambodia, Tongkin, extending north 
to Central China, with three species in Ceylon, 
and a reputed single outlier in the Andaman Islands. 
The Philippine Islands are credited with four species, 
but the absence of a vertical barrier on the parietal 
wall renders their position in the genus somewhat 
doubtful; as the anatomy of the soft parts, how- 
ever, has not, to my knowledge been studied , it 
may be advisable for the present to retain these 
four species in Plectopylis. Many of the species are 
sinistral ; dextrorsity, however, is the rule. 

Plectopylis andersoni (figs, i.'ja-c), which was des- 
cribed by Mr. W. T. Blanford, in the "Proceed- 
ings of the Zoological Society" for 1869, p. 448, 





Fig. 17. — Plectopylis andersoni. 

was found near Bhamo and Ava, in Upper 
Burma, and on the Yun-nan frontier. It is a 
solid, disc-shaped shell, measuring 24 to 26 
millimetres in diameter, of a light brown colour, 
with alternating streaks of a lighter shade on the 
upper surface. It is composed of eight whorls, 
distinctly ribbed above and below, and very 
regularly decussated above by raised spiral lines 
reaching as far as the apex of the shell, the base is 
also spirally sculptured, but the sculpture is less 
distinct ; the mouth of the shell is unarmed, but the 
parieial callus forms a raised curved ridge which is 



distinctly free at both ends from the peristome. 
The armature, which is comparatively simple, 
occurs a little beyond the middle of the last whorl, 
and consists of a simple strong vertical plate on the 
parietal wall (see fig. 17a), giving off at its upper 
extremity a very small horizontal tooth on the 
posterior side and a short horizontal lamella, 
I, 5 millimetres long, on the anterior side, while 
at its lower extremity there is a slight callus on 
the posterior side. The vertical parietal plate 
is shown sideways in fig. ijb, where also the 
palatal teeth are seen as they appear from the 
posterior end. Fig. lyc, gives the inside view of 
the outer wall, exhibiting the palatal armature. 
The palatal armature consists of four principal 
horizontal lamellae terminating posteriorly in a 
triangular conical tooth ; above these are : first 
a minute tooth, and secondly, higher up, a small 
fold near the suture, while at the base of the 
palatal wall are also : first a minute tooth, and 
secondly, nearer the suture, a small fold. The 
specimen figured is from Mr. Ponsonby's collection. 
Plectopylis bracliydiscus (figs. i8a-c) was described 
and figured by Lieut. -Colonel Godwin- Austen, in the 
"Journal of the Asiatic Society of Bengal," xlviii. 






Fig. iS.— Plectopylis brachydiscus. 

(1879), p. 2, t. I, f. I, from specimens found on the 
highrange of Mule-it, eastofMoulmein,Tenasserim. 
As in that work, however, the palatal arma- 
ture is not figured, I am glad to be able to 
supplement the figures there given. The speci- 
men now figured, from Mr. Ponsonby's collection, 
is old and weatherworn, and it does not possess 
the marginal fringe of hairs shown in Lieut. -Colonel 
Godwin-Austen's figure. The shell is described 
as being of a dull umber brown ; it is disk- 
shaped and regularly coiled, consisting of seven 
whorls, finely ribbed and spirally striated above ; 
it measures 19 millimetres in diameter. The 
peristome is strongly reflected and the parietal 
callus has a strong, raised, flexuous ridge, 
separated from the peristome, and has, in 
addition, about the middle, a free lamella, 3 
millimetres long (see fig. i8a). The parietal 
armature consists further of a broad, vertical 



.rtclVEMHF:!, J896. — No. 30, Vol. 3. 



SCIENCE-GOSSIP. 



155 



plate, angulated above, and giving off at its lower 
end towards the aperture, a horizontal plate, 4 
millimetres long, which slopes abruptly towards 
the parietal wall and gradually loses itself, while 
on the posterior side there is a very short ridge 
abruptly sloping obliquely downwards (see figs. 
i8a and b) ; about the middle of the vertical 
plate a free horizontal plate occurs, about 7 
millimetres long, separated from the vertical plate 
by a distance of i millimetre, decreasing in 
height as it approaches the aperture, and 
then suddenly terminating (see fig. 18a.) The 
palatal armature is very curious (see fig. i8f, 
which shows it in situ), and consists of six folds : 
the first straight and horizontal ; the second also 
straight and horizontal, but with a small bifurca- 
tion at the posterior end ; the third partly horizontal 
and deflecting posteriorly at an obtuse angle ; 
the fourth very short horizontally, descending ver- 
tically for a short distance and then deflecting 
posteriorly ; the fifth very short, flexuous, and nearly 
vertical ; while, finally, the sixth is again almost 
horizontal. A little below, and to the left of the 
sixth fold, is a small tooth, while above, posteriorly 
to the first fold, and almost in a line with the bifur- 
cation of the second fold, are three minute teeth. 

Pledopylis perarcta (figs, iga-c) was described by 
Mr. Blanford in the " Journal of the Asiatic Society 
of Bengal," xxxiv. (1865), part 2, p. 75, and first 
figured by Dr. L. Pfeiffer in " Novitates Con- 
chologicae," iii. (1867-1869), t. 108, f. 13-15. The 




a b c 

Fig. 19. — Pledopylis perarcta. 

armature was figured by Lieut. -Colonel Godwin- 
Austen in the "Proceedings of the Zoological 
Society" for 1874, t. 74, f. 4. The species was 
discovered at Mya Leit Doung, near Ava, Upper 
Burmah, but the specimen now figured is from 
Hlindet, and is in the collection of Mr, Ponsonby. 
The shell is sinistral, disk-shaped, somewhat thin and 
fragile, and composed of six closely-coiled whorls, 
ribbed regularly above, smoother below, widely and 
deeply umbilicated. It measures 10 millimetres 
in diameter. The parietal armature is composed 
of a broad vertical plate, angulated above, but 
gradually decreasing towards the base, where it 
is also slightly deflected posteriorly. A horizontal 
lamella rises anteriorly about its middle, very close 
to it, yet distinctly separate (see fig. iga), 
proceeding parallel to the whorl, deflecting with 
it towards the aperture and joining the raised 
flexuous bilobed ridge of the parietal callus, which 



is separate from the peristome (see fig. igc). 
Another horizontal but very short lamella, below 
the principal one, also rises close to the vertical 
plate ; a short free horizontal lamella is seen below 
the vertical plate, but it does not pass beyond it 
posteriorly (see fig. 19a ; this third horizontal 
lamella is also shown sideways in figs, igb and c). 
Lieut. -Colonel Godwin-Austen, in comparing the 
present species with Pledopylis pseudophis, states 
that the horizontal lamella is not continuous, and 
it is shown to be interrupted in his figure (Proc. 
Zool. Soc, 1874, P- *5o9, t. 74, f. 4), and again, in 
describing Pledopylis brachydiscus (Journ. Asiat. 
Soc, Bengal, xlviii. (1879), p. 2), he informs us 
that that species resembles P. perarda in this 
respect. The specimen here figured, however, has 
the principal horizontal lamella continuous, a fact 
which induced me at first to doubt the specific 
identity of the shell figured by me with P. perarda, 
but as the second horizontal lamella is joined tu 
the vertical plate in P. pseudophis and in my 
specimen this lamella is quite free, as stated to 
be the case in P. perarda, it is evident that my 
shell is not P. pseudophis; moreover, Mr. Blanford, 
in describing the shell, states that from the centre 
of the curved ridge at the aperture, "a lamella 
runs up the whorl towards the parietal plication." 
It may, therefore, safely be assumed that in 
the type specimen the horizontal lamella is 
not interrupted, and the question arises whether 
the shell figured by Lieut. - Colonel Godwin- 
Austen was perfect in having the horizontal 
plate interrupted in the manner described. The 
palatal armature is simple, and consists of four 
short, somewhat strong horizontal folds, equi- 
distant and parallel, with a smaller one above, 
close to the suture, and two small ones in a line 
with each other below, also near the suture (see 
figs, igb and c, the former figure showing the 
posterior, and the latter the anterior ends of the 
folds ; of the two bottom folds only one is visible 
in either figure). 
Pledopylis shiroiensis (figs, -zoa-d) is allied to the 







Fig. 20. — Pledopylis shiroiensis. 

preceding species, and is likewise sinistral, hv± the 
shell is smaller, measuring 75 millimetres Ic. 



156 



SCIENCE-GOSSIP. 



diameter, it is more raised in the spire and the last 
whorl is less deflected in front ; there are also diffe- 
rences in the armature as indicated below. The 
species was described and figured by Lieut. - 
Colonel Godwin-Austen in the " Proceedings of 
the Zoological Society " for 1874, p. 609, t. 
73. f- 3i where he states that it occurred in 
great abundance on the slopes of the peak of 
Shiroifurar, north-east of Munipur, at an altitude 
of 8,000 to 9, 000 feet, and only in the short 
grass skirting the edge of the forest. The specimen 
figured is from the Daffla Hills, and is in the 
collection of Mr. Ponsonby. The parietal armature 
is similar in character to that of P. perarcta, but 
the principal horizontal plate is more flexuous, being 
somewhat raised towards the vertical plate and again 
towards the aperture before its final deflection at 
its junction with the parietal callus ; it is also much 
broader. The second horizontal plate is also 
broader and flexuous, while both are a little more 
distant from the vertical plate (see fig. 20a). The 
vertical plate is smaller than in the species just 
mentioned, and rounded at the top, while it is not 
deflected posteriorly below as in that species. 
There are, besides, two small very short ridges 
given off from the extremities of the vertical plate 
on its posterior side ; the third horizontal fold is 
also a little longer as well as more flexuous than 
in P.perarcta. The chief difference, however, is in 
the palatal plates, as may be seen on reference to 
figs, -zoh-d. The first is horizontal, small and 
bilobed, close to the suture, then come two hori- 
zontal plates, small but comparatively broad, next 
a broad and strong vertical bilobed lamella, giving 
off on the posterior side two short ridges from the 



iryrrr^ 






Fig. 21. — Plectopylis de.xtrorsa. 

base of the lobes (see fig. 2od), and below this a 
small but broad horizontal plate with a small 
tooth a little above and posterior to it. Fig. 20& 
shows the barriers from the side of the aperture, 
and fig. 2.0c from behind. 

Plectopylis dextrorsa (figs. 2ia-c) was originally 
described by Mr. Benson in " Annals and Maga- 
zine of Natural, History " (3), v. (i860), p. 246, as a 
daxtral form of P. hiophis, from Tenasserim, and it 



was figured in Hanley and Theobald's " Concho- 
logia Indica," t. 13, f. 9, and in Tryon's "Manual 
of Conchology " (2), iii., t. 35, f. 2, as P. refuga, var. 
dextrorsa. Lieut-Colonel Godwin-Austen was the 
first to point out its specific distinctness from 
P. hiophis (Proc. Zool. Soc, 1875, p. 44), and he 
raised it to specific rank under the name of 
Plectopylis dextrorsa. He further stated that it is 
very close to P. pseudophis, but his figure of that 
species (loc. cit., 1874, t. 74, f. 3) does not bear out 
this view, and, after a careful comparison, I am 
inclined to consider its nearest ally to be 
P. br achy discus. The shell, however, is smaller 
than that of the last-named species, measuring 
16 millimetres in diameter, and there are 
differences of importance in the armature. The 
parietal vertical plate is rounded at the top, 
and forms a short ridge posteriorly, while 
another but much smaller ridge is formed at 
the base, first proceeding a little horizontally and 
then deflecting a little towards the suture (see 
fig. 2i«) ; the principal horizontal plate begins at 
a little distance from the vertical plate as in 
P. br achy discus, but it is placed above the middle 
and therefore nearer the suture than in that species, 
and instead of revolving parallel with the suture it 
bends upwards a little and proceeds without 
interruption as far as its junction with the raised 
ridge of the parietal callus (see fig. 21a) at the 
aperture, while in P. brachydiscus it is inter- 
rupted. Other differences in the palatal armature 
will be observed on reference to fig. 216, where the 
inner side of the shell wall bearing the folds and 
teeth is shown. The first plate is long and hori- 
zontal ; the second is also horizontal, and bifurcates 
as in the other species ; next come two series of 
three folds each, the anterior ones horizontal, the 
posterior ones smaller and obliquely descending ; 
and lastly we have a strong broad tooth parallel 
with and near to the suture, with a smaller one 
posteriorly in a line with it. Fig. 21c shows the 
barriers of this species — parietal and palatal — from 
the posterior side. 

P.S. — With the Editor's permission I take this 
opportunity of mentioning, that as yet I have been 
unable to obtain specimens of the following species 
of the genus under consideration : Plectopylis 
diptychia, P. muraia, P. oglei, P. tmmipurensis, P. 
feddeni, P. biforis, P. jugatoria, P. revoluta, P. 
phlyaria, P. vallata, P. eugeni, P. lambacensis ; and 
that I should much like to be favoured with them, 
either on loan or otherwise. In the case of mala- 
cologists having duplicate specimens, I should 
hope to be able to make a suitable exchange, as 
for instance. Gorilla fryae, the new species described 
in the September number of this magazine. — 
Address : 5, Giesbach Road, Upper Holloway, 
London, N. 

(To be continued.) 



SCIENCE-GOSSIP. 



178 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 

(Continued from page 156.) 



'PLECTOPYLIS ponsonbyi (figs. 22a-e), from 
■^ Hlindet, Burma, was described by Lieut. - 
Colonel Godwin -Austen in the " Proceedings of the 
Zoological Society "for 1888, p, 243. My draw- 
ing has been prepared from the specimen figured 
by Mr. Pilsbry in " Manual of Conchology," ix. 
(1894), t. 40, figs. g-i2. The shell is sinistral, 
disk-shaped, flattened above, with the apex a little 
raised, composed of six and a-half whorls, closely 
and regularly coiled, rounded and gradually in- 
creasing ; it is regularly and finely ribbed, and has 
the last whorl deflexed in front ; the parietal callus 
has a raised flexuous ridge, which is separate above 
and below from the peristome. From the aperture 
may be discerned a short, free, slightly curved, 
parietal fold, which follows the deflexion of the 
last whorl (see fig. ■22a). The parietal armature 




Fig. 22.— Plectopylis ponsonbyi. 

further consists of two strong vertical plates, the 
posterior one of which is the longer of the two ; 
it gives off posteriorly at the upper extremity a 
very short horizontal ridge, and at the lower 
extremity another short, but stronger, ridge, which 
descends obliquely ; the anterior plate is shorter 
but much stronger and thicker than the posterior 
one, and it gives off two strong ridges, one from 
the upper and one from the lower extremity, 
gradually decreasing in height. Below these two 
vertical plates there is a very thin horizontal fold 
terminating posteriorly a little beyond the posterior 
vertical plate, and anteriorly becoming attenuated 
till it is scarcely visible at the parietal ridge, to 
which, however, it is united. In the figure referred 
to, I regret to find this horizontal fold is wrongly 
shown as terminating a little beyond the anterior 
vertical plate. The palatal armature consists 

December, 1896.— No. 31, Vol. 3. 



of : first, a thin horizontal plate, parallel with and 
near to the suture, a little broader in the middle ; 
secondly, a somewhat stouter plate, slanting a little 
downwards posteriorly, also a little broader in the 
middle, and decreasing abruptly anteriorly, but 
very slowly posteriorly, where it is slightly 
indented ; thirdly, a similar plate, slanting a little 
more posteriorly, with a slight indentation ; 
fourthly, a stout bilobed vertical plate giving off 
anteriorly at the upper extremity a very slight 
ridge and posteriorly from the base of each lobe a 
short ridge ; fifthly, a horizontal fold parallel with 
and near to the lower suture, raised in the middle, 
with the apical portion reflexed and angular; it 
has a very small tooth on the posterior side. 
Another very small tooth is situate a little below 
the first horizontal plate about its middle, shown 
erroneously in fig. 22(f in a line with it. Fig. 22b 
shows the whole armature from the side of the 
aperture, fig. 22c the same from behind, and fig. 
22d the inside of the outer wall with the palatal 
folds (all magnified) ; while fig. 22f shows the shell 
restored, from above, natural size. The type 
specimen measures 18 millimetres in diameter, and 
is in Mr. Ponsonby's collection. 

Plectopylis fultoni (figs 23a and b) was described 
by Lieut. -Colonel Godwin-Austen in " Annals and 
Magazine of Natural History " (6), x. (1892), p. 
300, where the habitat of Khasi Hills, India, is 
doubtfully given, but the exact locality is unknown. 
The species was subsequently figured in Mr. 
Fulton's advertisements in "Nature" and "The 
Nautilus," and these figures were incorporated by 
Mr. Pilsbry in his " Manual of Conchology" (vol. 
ix., t. 40, ff. 13-15). As, however, the armature 
has not hitherto been figured, I am pleased to 
have an opportunity of doing so. The shell 
is sinistral, subglobosely disk-shaped, widely 
umbilicated, of a pale ochreous colour, regularly 
ribbed and decussated by a fine spiral sculpture ; it 
is composed of seven or seven and a-half whorls, 
very slowly increasing in width, the last of which 
descends in front ; the body whorl bears four rows 
of coarse hairs revolving horizontally over its 
whole length, the first on the keel, the second a 
little below the first, the third midway between the 
second and fourth, the latter being near the 
umbilical angulation. The peristome is reflexed 
and thickened ; the parietal callus is only slightly 
thickened, its margin, however, is distinctly 
separated from the peristome above and below ; 
the aperture is devoid of armature. The shell 
measures 18 to 20 millimetres in diamexer. The 



179 



SCIENCE-GOSSIP. 



parietal armature consists of a single strong 
vertical plate (see fig. 23a). Lieut. -Colonel 
Godwin-Austen, in describing the armature (loc. 
cit.), states that the parietal plate has only a slight 
horizontal support above on the posterior side ; 
in the tv/o specimens in my possession, however, 
this plate has a similar support below ; these 
supports consist of a tooth united to the vertical 
plate by a slight callosity. Below this is a short 




Fig. 2^.—Plectopylis fitltoni. 

thin horizontal plate, a little indented in the 
middle. The palatal armature (see fig. 236) 
consists of : first, a short horizontal fold, close to 
and parallel with the suture ; secondly, a longer 
and stouter horizontal flexuous fold ; thirdly, 
another horizontal fold, slightly indented in the 
middle and deflexed posteriorly at an obtuse angle ; 
fourthly and fifthly, two series each of two short 
horizontal folds, the anterior ones slightly oblique, 
with their lower ends towards the aperture, and the 
posterior ones deflexed at an obtuse angle posteriorly; 
and sixthly, near the base, a short slightly bent 
fold, with the convex side turned towards the 
lower suture. The specimen figured, which is 
not quite mature, bears a second vertical plate on 
the parietal wall (see fig. 23a), which appears to be 
the remnant of the immature barriers formed before 
the completion of the shell, for, as will be seen later 
on, in this genus, as in Corilla (see ante p. go), the 
armature is not confined to full-grown shells, but 
occurs at various periods of their existence, the 
earlier sets of plates and folds being absorbed after 
the formation of the next set. A young specimen 
in my collection, composed of five whorls, possesses 
the armature a little beyond the place where four 
and a-half whorls have been completed ; the 
barriers are almost identical with the mature ones, 
except that the folds are smaller and the second 
and third palatal folds are deeply bilobed. A still 
younger specimen of only four whorls has the 
armature near the place where three and a-hal 
whorls have been completed. Plectopylis fuUoni is 
allied on the one hand to P. andersojii (see ante p. 
154' fig- 17). the parietal armature being almost 
identical, while the arrangement and structure of 
the palatal folds connect it on the other hand with 
P. pledostoma, to be considered in a subsequent 
paper. 

The species of Plectopylis hitherto dealt with 
belong to a group forming a section of the 



genus, the members of which, with perhaps one 
exception, do not occur north of the Himalayan 
range, but are confined to the vast tract to the 
south of it, comprising India, Burma, and Farther 
India. Before dealing with the remaining members 
of this section, exigencies of illustration compel 
me to consider the Chinese members of the genus, 
which constitute another section characterized by 
a glossy, more or less transparent shell and a 
somewhat less complicated armature. All the 
known species are dextral. 

Plectopylis Jjtnbi'iosa {&gs. 24a and b), was described 
and figured by Dr. E. von Martens, in the " Jahrbuch 
der Deutschen Malakazoologischen Gesellschaft," 
ii. (1875), p. 128, t. 3, f. 6, from specimens col- 
lected in the Province of Kiang-si of China : it 
has subsequently been found in the Province of 
Hou-Nan. Dr. O. F. von Mollendorff, in figuring 
the armature of this species (op. cit. x. (1883), t. 12, 
f. 11), has given only the anterior aspect of the 
plates and folds, while my figure (fig. 24a) shows 
the posterior view. The shell is disk-shaped, with 
the spire a little elevated, subpellucid, corneous, 
composed of six whorls slowly increasing ; strongly 
and regularly ribbed above, with a strong spiral 
sculpture, smoother and shining below, with a 
yellowish band round the wide open umbilicus ; 
angulated on the periphery, which is provided with 
a fringe of coarse lacinia ; the white peristome is 
strongly reflexed, and a little thickened, and the 
parietal wall is without a callus ; the shell measures 
15 millimetres in diameter. The parietal armature 
consists of a strong, simple, vertical, lunate plate, 
the convex side of which is turned towards the 
aperture, and the lower extremity is somewhat 
strongly deflexed posteriorly ; on the anterior side 
are found two short horizontal teeth, one above 
and one below, in a line with the extremities of the 
vertical plate, the upper one being the stronger 
of the two (see fig 246). The palatal armature 





Fig. 24. — Plectopylis fimbnosa. 

consists of six short, simple, horizontal folds, the 
first near to and parallel with the suture, the 
second longer and stouter, nearly opposite the 
upper extremity of the parietal plate; the third, 
fourth, fifth and sixth all parallel, equidistant, and 
gradually decreasing in length downwards ; a small 
tooth occurs a little above and posteriorly to the 
sixth fold ; these folds are visible externally 
through the shell wall. The three specimens in 
my collection are from Kioo-Kiang, Province of 
Kiang-Si, and are all identical in armature. One 



SCIENCE-GOSSIP. 



180 



specimen is of special interest from possessing, in 
addition to the mature plates, the remains, partly 
absorbed, of the previous set, consisting of the 
basal portion of the parietal plate, the whole of the 
first palatal fold, parts of the second and fourth, 
and the whole of the fifth and sixth, with the 
adjacent tooth. Here we have, therefore, absolute 
proof of the absorption of the earlier armature as 
suggested in the case of Corilla. 

The Rev. Vincenz Gredler described a variety of 
this species under the name of P. fimbriosa var. azona 
(Jahrb. Deutsch. Malak. Gesells, xiv. (1887), p. 369), 
which, subsequently, he raised to specific rank 
(" Nachrichtsblatt der Deutschen Malakazoolo- 
gischen Gessellschaft," xxi. (1889), p. 155). In order 
to ascertain whether any difference in the armature 
could be detected, I have opened the single speci- 
men in my collection (from Patong, West China), 
but with the exception of the tooth near the sixth 
palatal fold being absent and the palatal folds 
generally being a little shorter, it is identical, and I 
am, therefore, of opinion that this form must be 
regarded as a variety, as originally suggested by 
Mr. Gredler. It is smaller than the type, measur- 
ing only 12 millimetres in diameter, a little 
darker and less shining, and it is devoid of the 
yellowish zone round the umbilicus, so that the 
varietal name suggested is very appropriate. Dr. 
von Mcillendorff has named a variety nana, which 
differs from the type in having the last whorl with 
a more acute peripherial angle and in being much 
smaller, the measurement given being 6 milli- 
metres. I do not know this variety, and have, there- 
fore, had no opportunity of studying its armature. 

Pledopylis pulvinaris (fig. 25) was described by 
Dr. A. A. Gould in the " Proceedings of the Boston 
Society of Natural History," vi. (1859), p. 424, 
from specimens collected in Hong Kong and in 



Fig. 2^.-I'lectopyUs pulvinaris. 

China, near Canton. It was also collected in 
Hong Kong by Dr. von Martens, who figured the 
species in " Die Preussische Expedition nach Ost- 
Asien," Zoologischer Theil, ii. (1867), t. 14, f. 9, 
and this figure has been copied by Mr. G. W. 
Tryon in his "Manual of Conchology " (2), iii. 
(1887), t. 33, ff. 29-31. It was likewise figured 
by Dr. von Mollendorff in the " Jahrbuch der 
Deutschen Malakazoologischen Gesellschaft," x. 
(1883), t. 12, f. 9, and by Dr. W. Kobelt in Martini 
und Chemnitz' " Conchylien Cabinet," ii. (1894), t- 
205, ff. 12-14. The shell is disk-shaped, widely per- 
spectively umbiHcated, pale corneous brown, com- 
posed of six closely regularly coiled whorls, finely 
striated above with very minute spiral sculpture 
scarcely visible under a strong lens ; the spire is 



almost flattened, with the apex a little raised ; the 
last whorl widens toward the aperture and is 
a little defiexed in front. The armature consists 
of a strong lunate vertical plate on the parietal 
wall, strongly deflexed posteriorly, the convex side 
towards the aperture, with two short horizontal 
teeth on the anterior side, one above and one 
below, in a line with the two extremities, the 
upper being the stronger of the two. The 
palatal wall bears seven horizontal folds ; the 
first thin, near to and parallel with the suture, 
the second, third, fourth, and fifth, larger 
and stronger than the first, almost parallel 
to each other, equidistant and descending a little 
obliquely posteriorly ; the sixth smaller and 
parallel with the lower suture. There are in 
addition, behind the principal folds, two small 
teeth, one in a line with the fifth fold and more or 
less connected with it, the other midway between 
the fifth and sixth folds. The second fold is a 
little indented posteriorly so that a separate 
denticle is almost formed. The specimen figured 
is from Hong Kong, and measures 16 millimetres 
in diameter. A specimen in Mr. Ponsonby's 
collection is larger, measuring 22 millimetres 
in diameter ; the shell is darker, thicker, rugosely 
striated, and the spiral sculpture is more 
decided ; the whorls are more tumid and the 
peristome is much more reflexed and thickened, 
while the margins are connected by a whitish 
callus which bears a slight denticle. This 
specimen probably belongs to P. pulvinaris var. 
continentalis, described by Dr. von Mollendorff 
(Jahrb. Deutsch. Malak. Gesells. xii. (1885), p. 
388), from Canton. The shell figured by Dr. 
Kobelt (op. cit.) bears a similar denticle on the 
parietal wall. Mr. H. Fulton has obligingly sent 
me for examination, ten specimens of this species, 
the smallest of which measures 16 millimetres, 
and the largest 20 millimetres in diameter ; of 
these, five, including the smallest and the largest, 
possess the denticle on the parietal callus, and two 
more have a rudimentary denticle. 

Plectopylis cutisculpta (figs. 26a-c), from Fud-Shien, 
was described by Dr. von Mollendorff, in the 
" Jahrbuch der Deutschen Malakazoologischen 
Gesellschaft," ix. (1882), p. 184, and figured by 
him in the same work, x. (1883), t. 12, f. 12. The 
shell is disk -shaped, with the spire a little raised 
and composed of six or seven slowly increasing 
whorls, finely ribbed above, smooth and shining 
below ; the last whorl scarcely descends in front, 
the umbilicus is wide and open, and the peristome 
is a little reflected, the specimen figured measures 
7 millimetres in diameter. The parietal armature 
consists of a strong vertical plate, a little convex 
towards the aperture, with a slight angular callosity 
anteriorly at the lower extremity, and with a little 
ridge above and below posteriorly ; on the posterior 



i8i 



SCIENCE-GOSSIP. 



side are, besides, two minute folds, one horizontal 
near the upper extremity, the other vertical near 
the lower extremity, the latter being the larger of 






Fig. 26. — Plectopylis cuiisculpta. 

the two (figs. 26a and b). The palatal armature 
consists of six folds more or less horizontal, the first 
short and thin, near the suture, the second a little 
larger, bilobed ; the third, fourth, and fifth longer, 
broader, obliquely descending posteriorly, and 
each giving off a minute denticle ; the sixth very 
short as seen in fig. 26c. (The first fold has 
accidently been omitted in this figure.) The 
specimen is in Mr. Ponsonby's collection. 

Plectopylis multispira (figs, ^ja-d), from the 
Province of Hou-Nan, was described by Dr. von 
MoUendorff in the " Nachrichtsblatt der Deutschen 
Malakazoologischen Gesellschaft," xv. (1883), p. 
loi, and figured by him in the " Jahrbuch Deutsch. 
Malak. Gesells. x. (1883), t. 12. f. 10, The shell 
is thin, subpellucid, yellowish corneous, shining 
above and below, widely umbilicated, composed of 
seven closely and regularly coiled whorls, gradually 
and slowly increasing, finely striated, the last 
whorl being wider and shortly deflected in 
front. It measures from 8 to 11 millimetres in 
diameter. The parietal armature is composed 




Fig. 27.— Plectopylis multispira. 

of a strong lunate plate which descends obliquely 
posteriorly, the convex side being towards the 
aperture (fig. 27a) ; on the anterior side are found : 
first, a short horizontal fold in a line with the 
upper extremity of the vertical plate ; below this, 
almost in a line, are five minute denticles, the 
second auA third of which are united so as to form 



a double one, while the fifth is a little elongated and 
slants obliquely downwards (see figs. 27* and c). 
The palatal armature (figs. 27^, b, and d) is composed 
of six more or less horizontal folds : the first very 
short and thin, near the suture ; the second, third, 
fourth, and fifth stronger and broader, equidistant and 
parallel, obliquely slanting downwards, and slightly 
indented posteriorly ; the sixth a little narrower, 
near the lower suture ; between the fifth and sixth 
folds, a little beyond their posterior extremities, is 
found a little elongated denticle. Fig. 27^ shows 
the whole armature from the posterior side, fig. 276 
from the anterior side, while fig. 27^ shows the 
inner side of the outer wall with its folds. The 
specimen figured is in my collection, and measures 
10 millimetres in diameter. 

Plectopylis invia (figs. 28a and b) was described 
and figured by the Rev. P. Heude, in Part 2 of his 
' ' Notes sur les Mollusques Terrestres de la Vallee du 
Fleuve Bleu," published in the " Memoires con- 
cernant I'Histoire Naturelle de I'Empire Chinois " 
(1885), p. Ill, t. 30, f. 4, from specimens collected 





Fig. 28. — Plectopylis invia. 

in Tchen-Keou. The shell somewhat resembles 
P. mtiltispira in outline and texture, but it is 
more strongly ribbed and less transparent ; it is 
composed of only six whorls and it measures only 
8 millimetres in diameter; the umbilicus is very 
deep. The parietal callus forms a raised ridge, not 
continuous with the margins of the peristome, and 
giving off a little above the middle a short entering 
fold. The parietal armature (see fig. 28a) further 
consists of a slightly curved vertical plate, giving 
off anteriorly at the upper extremity a very slight 
horizontal support. The specimen here figured 
has, in addition, a second smaller vertical fold 
posteriorly to the principal one, but whether this 
is a normal condition I am unable to say, having 
only a single specimen to examine. The principal 
vertical plate has also posteriorly a slight support 
at the lower extremity. The palatal armature 
consists of five folds, the first, facing the upper 
extremity of the parietal fold, thin and longer than 
the others, attenuated anteriorly and nearly 
horizontal; the second, third, and fourth are short 
and broad, very oblique, almost vertical, and con- 
nected by a slight attenuated callous ridge, which 
is continued below the fourth fold ; the fifth is 
thin, horizontal, and situate near the lower suture 
(see fig. 28b). The specimen which I have been 
allowed to open is in Mr. Ponsonby's collection ; 
it measures 65 millimetres in diameter. 
(To be continued.) 



SCIENCE-GOSSIP. 



204 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 
(Continued from page 181.) 



T N speaking of Plectopylis fimhriosa, var. azo7ta {ante 
p. 180), I stated that the only difference 
between its armature and that of the type, appeared 
to be that the palatal folds were shorter and that 
the tooth near the sixth fold was absent. Since 
writing, the Rev. Vincenz Gredler, of Bozen, 
Austria, who described the variety, has kindly 
placed two additional specimens at my disposal, 
and these confirm my statement. The specimens 
are, however, a little smaller than my own, 
measuring only 1 1 millimetres in diameter. 

Mr. Gredler has also favoured me with three 
specimens of Plectopylis invia, two of which I opened 
in order to ascertain whether the second vertical 
parietal plate already referred to (ante p. 181) was 
constant, and as both specimens possess this plate, 
it may reasonably be inferred that it is a constant 
feature. In this connection, however, it is worth 
mentioning that Lieut. - Colonel Godwin - Austen 
(Proceedings of the Zoological Society, 1874, 
p. 609) records the presence of two vertical parietal 
plates in a specimen of Plectopylis serica, a species 
normally provided with only one vertical parietal 
plate, and he thinks that to this reduplication of 
structure is due the more compound forms of 
armature in the Burmese species of the genus. 

The same naturalist draws my attention to the 
fact that there must be an error in the second 
locality (Dafia Hills), mentioned by me for Plectopylis 
shivoiensis {ante p. 156), as he believes that no 
European has been in those hills since he collected 
there, and he did not find the species in question. 
The shell I figured as from the Dafla Hills is, in 
Mr. Ponsonby's collection, so labelled, but, as it 
was collected by Mr. Godwin-Austen, the locality 
may now, on his authority, be safely altered to 
Shiroifurar, which is 150 miles from the Dafla 
Hills, and is the place from which the species 
was originally described. 

Plectopylis stenochila (figs. 29 a~d), from Badung, 
in the Chinese province of Hoo-Pe, was described 
by Dr. von Mollendorff in the " Nachrichtsblatt 
der Deutschen Malakazoologischen Gesellschaft," 
1885, p. 165, and in the " Jahrbuch " of the same 
society, xiii. (1886), p. i85. The shell is disk- 
shaped, with a slightly elevated spire, and is com- 
posed of six and a-half or seven whorls, which are 
closely coiled and increase very slowly and regu- 
larly, the last whorl descending a little anteriorly. 
It is very finely and regularly ribbed and decussated 
by fine spiral Hnes both above and below ; in addi- 
tion the periostracum is raised into deciduous plaits, 
which are especially conspicuous below, and form 

January, 1897.— No. 32, Vol. 3. 



a laciniated fringe round the angular periphery. 
The peristome is white, a little thickened and 
reflexed, while the parietal callus forms a slightly 
raised, scarcely flexuous ridge which is separate from 
both margins of the peristome ; the aperture is 
almost round and is without folds. The parietal 
armature consists of a somewhat strong vertical 
lunate plate, its convex side facing the aperture and 






Fig. 29. — Plectopylis stenochila. 

a little deflexed posteriorly at the lower extremity. 
On the anterior side there are, besides two short 
horizontal folds, one above and one below, in a 
line with the two extremities of the vertical plate, 
and between these two folds occur four small 
denticles, the two lower of which are united so 
as to form a double one (see fig. 2gb). The 
palatal armature consists of six folds : the first, 
short horizontal and near the suture ; the second, 
third, fourth, and fifth larger and stronger, parallel 
to each other and descending a little obliquely 
posteriorly; and the sixth again short, horizontal, 
and near the lower suture (see fig. 2gd, which 
shows both armatures from the posterior side, and 
fig. 29c, which shows the inside of the outer wall 
with its palatal folds). The specimen figured is in 
Mr. Ponsonby's collection, and measures 8 milli- 
metres in diameter. Mr. Gredler has favoured me 
with three additional specimens, which differ slightly 
from the one figured in having only one simple 
besides the double denticle on the parietal wall. 
The species is closely allied in its armature to 
Plectopylis multispira {ante p. 181, fig. 27), but the 
shell is smaller, more raised in the spire, and has 
one whorl less, while it is less shining and trans- 
lucent than that species. On the other hand it is 
also allied to Plectopylis murata, to be considered in 
a future article. 

Plectopylis laminifera (figs, -^oa-c), from Hoo-Pe, 
China, was described by Dr. von Mollendorff, in 
the "Nachrichtsblatt der Deutschen Malakazoo- 
logischen Gesellschaft," 1885, page 164, and figured 
in the "Jahrbuch" of the same society, xiii. 



205 



SCIENCE-GOSSIP. 



(i8S6), t. 6, f. I. The shell is somewhat solid, 
disk-shaped, with a conical spire, hornish brown, 
somewhat coarsely and regularly ribbed, and 
decussated with spiral lines above and below, but 
somewhat smoother below, and is widely, deeply 
umbilicated. It is composed of six and a-half 
regularly coiled whorls, which widen very slowly ; 
the last whorl descends a little anteriorly, and 
is angulated at the periphery, which is pro- 
vided with a coarse laciniated fringe. The 
peristome is white, a little thickened and 
reflexed, and the aperture is rounded, without 
armature, while the parietal callus has a raised 
flexuous ridge which is almost united to the 
margins of the peristome. The parietal armature 
consists of a strong vertical lunate plate, the 
convex side facing the aperture and only slightly 
deflexed posteriorly at the lower extremity. On 
the anterior side are found two short horizontal 
folds in a line with the two extremities of the 
vertical plate ; midway between these folds is a 
denticle (see fig. 30a, which shows the shell with 
a part of the outer wall removed, exposing both 
armatures from the anterior side, and fig. 30^, 
which gives the posterior view, while fig. 30^ 
shows the inner wall separately ; all the figures 
are enlarged). The palatal armature consists 
of a small, short horizontal fold near the 
suture, and four stouter and larger, nearly hori- 
zontal folds, descending a little posteriorly (the 
second and fifth being a little longer than the third 
and fourth), and lastly, a short horizontal fold near 
the lower suture (see figs. 30a and b). The speci- 
men figured is in Mr. Ponsonby's collection, and 
measures 14-5 millimetres in diameter. Mr. 
Gredler has kindly placed at my disposal five 
specimens, only one of which, however, has the 
median parietal denticle ; two of the specimens 
measure only 11 5 millimetres in diameter, two 
others 14 millimetres, and one 13-5 millimetres; 




a be 

Fig. 30. — Plectopylis laminifera. 

they also vary a little in the height of the spire, 
some being more flattened than others. The species 
is closely allied to Plectopylis fimbriosa (see ante 
p. 179, fig. 24) ; its nearest ally, however, is 
P. reservata, which we shall have to consider in a 
future paper. 

Several other species of the Chinese group re- 
main to be dealt with, but exigencies of illustra- 
tion again compel me to break into the continuity 
of the series, and to revert to the Burmese and 
Indian 'jpecies. 



Plectopylis serica (figs. 3ia-f) was described and 
figured in the " Proceedings of the Zoological 
Society," 1874, p. 608, t. 73, f. 5, by Lieut. - 
Colonel Godwin-Austen, who first collected speci- 
mens on the peak of Henozdan, Burrail range, 
Naga Hills. Later he again found it abundant 
above 5,000 feet on the same range, as far east 
as the Kopameda ridge. He further states that 
it is essentially a forest species, found in the 
dead leaves and moss. The species was also 




a be 

Fig. 31. — Plectopylis serica. 

figured in Hanley and Theobald's " Conchologia 
Indica," t. 132, ff. 8 and g (1875), but by an 
error the name was printed sericata. The shell 
is dextral, disk-shaped, with a slightly raised spire, 
and is composed of seven narrow, closely-coiled 
whorls. It is of a dark corneous brown above, 
paler below, with narrow, oblique brown bands, 
especially conspicuous below, running parallel with 
the lines of growth. A distinctly angular, raised 
ridge runs a little above the suture nearly to the 
apex, the last whorl being bi-angulated at the 
periphery. It is regularly and finely ribbed, and 
distinctly decussated by microscopic spiral lines. 
The last whorl descends but little anteriorly, the 
peristome is a little thickened and reflexed, the 
upper part of its outer margin being slightly 
inflexed ; the parietal callus bears a very slightly 
raised curved ridge, which is united to the margins 
of the peristome, there being only a slight notch at 
the lower junction. The parietal armature consists 
of a single vertical plate, which descends a little 
obliquely towards the aperture ; the upper ex- 
tremity gives off on both sides a very short support, 
and at the lower extremity, also on both sides, a 
stronger support, the anterior one being a little 
lower than the posterior one (see fig. 31a). The 
palatal armature consists of five more or less 
oblique horizontal folds ; the first is longest, 
flexuous, and descends a little posteriorly ; the 
second is horizontal, and bifurcates posteriorly, 
the upper arm straight, the lower descending 
obliquely ; the third, shorter, at first proceeding 
horizontally, about the middle deflecting obliquely at 
an angle of about 100 degrees ; the fourth is a little 
longer, ascends a little at first and then deflects 
posteriorly at an angle of 90 degrees ; the fifth 
is shortest, horizontal, near the lower suture and 
parallel to it (see fig. 316, which shows the 
armatures, parietal and palatal, from the posterior 
side, and fig. 3 if, which shows the inside of the 
outer wall, with its palatal folds; all the figures 



SCIENCE-GOSSIP. 



206 



are enlarged). Mr. Godwin-Austen (op. cit., p. 60S) 
mentions six palatal folds, and his figure shows a 
small one near the upper suture, of which, how- 
ever, no trace is found in the specimen now 
figured, which is from Sylhet, and is in Mr. 
Ponsonby's collection; it measures n milli- 
metres in diameter. I have already alluded to the 
fact that Mr. Godwin-Austen found two vertical 
parietal plates in one specimen (ante p. 204). 

Pkctopylis pinacis (figs. 32«-rf), from Sikkim, was 
described by Mr. Benson in the " Annals and 




b c 

Fig. 32. — Pkctopylis pinacis. 

Magazine of Natural History" (3), iii, 1859, p. 268, 
and (3), V, i860, p. 247. The shell was figured in 
Hanley and Theobald's " Conchologia Indica," 
t. 13, f. 5 (1870), and t. 84, ff. 1-4 (1872), while the 
parietal armature was figured by Mr. Godwin- 
Austen in the " Proceedings of the Zoological 
Society," 1874, t. 74, f. i. Professor von Martens 
described what he thought was a new form, 
under the name of Helix {Gorilla) pettos, in 
the " Malakozoologische Blatter," xv, (1868), 
p. 158, and this was figured by Dr. Pfeiffer in 
" Novitates Conchologicae," iii, (1869), t. loi, 
ff. 7-9 ; the type specimen, which is in the 
" Konigliche Museum fiir Naturkunde," Berlin, 
was obligingly sent to me for inspection by 
Professor von Martens, with permission to open it ; 
he suspected that it might probably be the same as 
Pkctopylis pinacis, and upon opening the shell this 
proved to be the case, the armature being identical, 
while no differences could be detected in the shells 
themselves. Under these circumstances Professor 
von Martens' name becomes a synonym of the 
species now under consideration. The shell is 
sinistral, disk-shaped, pale corneous, widely 
umbilicated, finely regularly ribbed and decussated 
by spiral lines, composed of seven slowly increasing 
whorls, the last comparatively wide and a little 
deflexed anteriorly, and angulated at the periphery ; 
the peristome is thickened and reflexed, its margins 
united by the slightly raised, very flexuous, ridge 
of the parietal callus, which- has a slight notch at 
the junctions above and below. The parietal 



armature (fig. 321;), consists of a single strong 
vertical plate, which is strongly abruptly deflected 
anteriorly at the lower extremity, and gives off 
posteriorly a club-shaped support ; the upper 
extremity gives off two slight supports, one on 
either side, the posterior one horizontal, and the 
anterior one a little lower, oblique, and very 
short ; a little below the posterior support occurs a 
small denticle ; a free, thin horizontal fold is found 
below the vertical plate ; see also fig. 32a, which shows 
the shell with a portion of the outer wall removed, 
exposing the parietal and palatal armatures from 
the anterior side, and fig. 326, which shows the 
folds from the posterior side. The palatal arma- 
ture consists of : first, a thin horizontal fold near 
the suture ; secondly, a stronger horizontal fold, 
deflexed in the middle ; thirdly and fourthly, two 
shorter, but stronger, equal and parallel folds 
descending obliquely ; fifthly a crescent-shaped 
fold placed obliquely with the concave side facing 
the aperture (the lower surfaces of these folds are 
seen in fig. 32a, their upper surfaces in fig. 32?)) ; 
sixthly, a smaller horizontal fold, which becomes 
attenuated posteriorly (see fig. 32^) ; two minute, 
elongated denticles, one below the other, and 
placed at right angles to each other, occur 
between the first and second folds, near their 
posterior terminations. The specimen figured is 
from Darjeeling, and is in Mr. Ponsonby's collec- 
tion ; it measures 15 millimetres in diameter. 
A specimen in my collection, also from Dar- 
jeeling, measures 14 millimetres. Mr. Godwin- 
Austen's figure, quoted supra, shows a short free 
horizontal fold above the vertical parietal plate ; 
no trace of this fold can be seen in either of the 
two specimens examined, neither does it occur in 
the specimen in the Berlin Museum. 

Plectopylis nagacnsis (figs, 33^-^), was described 
and figured in the " Proceedings of the Zoological 




Fig- 33- — Plectopylis nagnensts. 

Society," 1874, p. 609., t. 73, f. 4, by Mr. Godwin- 
Austen, who found the species at Prowi, at the 
head of the Lauier River, Naga Hills, Assam. 
The shell is sinistral, widely umbilicated, disk- 
shaped, with a conical, raised spire, of a dark 



207 



SCIENCE-GOSSIP. 



corneous brown, composed of seven closely-coiled, 
slowly increasing, rounded whorls, the last of which 
descends a little anteriorly. It is finely striated 
and decussated by microscopic spiral sculpture, 
scarcely visibly on the earlier whorls, but more 
apparent below. The peristome is white, a little 
thickened and reflexed ; the parietal callus has a 
raised flexuous ridge separated, above and below, 
from the margins of the peristome. The parietal 
armature consists of a strong vertical plate, a little 
deflected posteriorly at the lower extremity, where 
it terminates in a short strong ridge ; it has also a 
short support a little higher up on the anterior side, 
and another short ridge on the posterior side at the 
upper extremity. Below this plate is a free thin 
horizontal fold, and a little above the middle of 
the plate, a short distance from it, rises a strong 
horizontal plate, which runs parallel with the 
whorl, and descends a little at the aperture, where 
it is united with the raised ridge of the parietal 
callus (see figs. 33a and b, which shows the shell 
with part of the outer wall removed). The palatal 
armature consists of: first, a thin bilobed hori- 



zontal fold near the suture ; secondly, a stronger 
horizontal fold, with a small denticle at its 
posterior termination (between these folds, in a 
line with their posterior terminations, is a 
minute denticle) ; thirdly, a horizontal fold, 
descending a little posteriorly, where it is 
slightly notched ; fourthly, a similar horizontal 
fold, deflected posteriorly, finally slightly raised 
and notched ; fifthly, a shorter but stronger hori- 
zontal fold with the posterior end more strongly 
deflected and also slightly notched ; sixthly, a 
thinner but longer horizontal fold near the lower 
suture, attenuated anteriorly (see fig. 33;^, which 
shows the inner side of the outer wall with its 
palatal folds). Between the posterior terminations 
of the fifth and sixth folds is found a very slight 
thin fold extending much further posteriorly than 
the main folds ; this may prove not to be constant ; 
it is not mentioned by Mr. Godwin-Austen in 
his description. The specimen figured is in 
Mr. Ponsonby's collection, and measures — major 
diameter, 11 -5 millimetres, minor diameter, 10 
millimetres, axis, 55 millimetres. 

(To be continued.) • 



SCIENCE-GOSSIP. 



244 



ARMATURE OF HELICOID LANDSHELLS. 

Bv G. K. GuDE, F.Z.S. 

(Continued from page 207.) 



JJLECTOPYLIS cydaspis (5gs. 34a-rf), from 
Tenasserim, Burma, was first described by 
Mr. Benson, under the name of Helix catinus, in the 
"Annals and Magazine of Natural History" (3), 
iii. (1859), p. 1S5, but that name being preoccupied 
in Helix he changed it to Helix cyclaspis (loc. cit., 
p. 273). Having received additional material, 
which enabled him to examine the armature, he 
subsequently published an amended description 
(loc. cit. (3), V. (i860), p. 245). The shell was first 
figured in Hanley and Theobald's " Conchologia 
Indica," t. 13, f. 10 (1870). The anatomy has been 
figured by Mr. F. Stoliczka in the " Journal of the 
Asiatic Society of Bengal," xl. (1871), p. 222, t. 15, 
ff. 4-6, and by Mr. Pilsbry in " Manual of 
Conchology, ix. (1895), t- 42, ff. 34-3G, while the 
palatal armature has been illustrated by Lieut. - 






Fig. 34. — Plcctopylis cyclaspis. 

Colonel Godwin-Austen in the " Proceedings of the 
Zoological Society," 1874, t. 74, f. 10. The shell is 
sinistral, depressed-conical, widely umbilicated, 
irregularly ribbed above, smoother below, hornish 
brown, with the suture margined ; it is composed 
of six and a-half or seven slowly increasing whorls, 
the last not descending in front, and having an acute, 
compressed keel . The peristome is thickened and re- 
flexed and its margins are united by a raised straight 
ridge; the parietal callus bears a short, strong 
horizontal entering fold, entirely visible from the 
aperture (see fig. 34^). The parietal armature con- 
sists of a strong and very complicated ramified plate, 
which ascends obliquely from the side of the aperture 
near to the suture, where it bifurcates, one arm — 
the upper one — ascending a little, then proceeding 

February, 1897.— No. 33, Vol. 3. 



horizontally, and finally becoming attenuated ; the 
lower and stronger one descends obliquely at an 
angle of 45^ for about half its length, then 
deflects almost vertically and gives off posteriorly 
at its base a short strong support. The lower 
extremity of the main plate gives off anteriorl} 
also a strong short support. Below the plate is a 
free, short, horizontal fold. The specimen shown 
with the outer wall removed in fig. 346 is not quite 
mature, and it possesses the former plate, which is 
evidently in course of absorption, as the second 
descending arm has almost disappeared, and the 
lower free fold is also very slight. The palatal 
armature consists of five folds : the first, thin, near 
and almost parallel with the suture ; the second, 
broad and flexuous, descending obliquely posteriorly, 
half above and half below the peripherial keel ; the 
third, also broad and somewhat crescent-shaped ; 
the fourth, very strong, broad and vertical, and 
intercalating with the main stem and lower branch 
of the parietal plate ; the fifth, thin, horizontal and 
parallel with the lower suture. Fig. 34c shows 
the parietal and palatal armature from the anterior 
side, while ^^d shows the inside of the outer wall 
with its palatal folds. At the base of the vertical 
palatal fold on the right side — i.e. posteriorly — 
occurs a small denticle, shown erroneously in 
fig. 34(f, on the left side. Fig. 34a shows a mature 
specimen, natural size ; the other figures are all 
magnified. The two specimens are from Moulmain, 
Burma, and are in the collection of Mr. Ponsonby. 
The mature specimen measures — major diameter, 
17 millimetres; minor diameter, 14.5 millimetres; 
axis, 7 millimetres. 

Plectopylis hareuorjcm (figs. 35^-^), from Pegu, was 
described by Mr. W. T. Blanford in the "Journal 
of the Asiatic Society of Bengal," xxxiv. (1865), 
part 2, p. 73, and figured by Dr. Pfeiffer in 
"Novitates Conchologicae," iii. (1869), t. loS, 
ff. 16-18, and in Hanley and Theobald's " Con- 
chologia Indica," t. 13, f. 6 (1870). The armature 
was figured by Lieut. -Colonel Godwin Austen in 
the " Proceedings of the Zoological Society," 1874, 
t. 74, f. 5. According to Mr. G. Nevill (" Handlist 
of MoUuscain the Indian Museum. Calcutta " (1878) 
p. 72), the species has also been found in the Arakan 
Hills. The shell is sinistral, disk-shaped, with the 
apex a little raised above the flattened spire, with 
a wide but shallow umbilicus, white with light 
chestnut strigations, finely ribbed, with micro- 
scopic spiral sculpture. It is composed of six 
closely-coiled whorls, which increase siow'y, the 



SCIENCE-GOSSIP. 



245 



last being a little wider than the preceding, 
angulated above the periphery and descending 
anteriorly. The peristome is white, somewhat 
thin, but reflexed ; the parietal callus has a raised 
flexuous ridge, separated from the lower margin of 
the peristome and notched at its junction with the 
upper margin. The parietal armature consists of 
a long horizontal fold, united to the ridge at the 
aperture, and proceeding parallel with the last 
whorl for a quarter of its length, at which point it 








<s^=^^- 



Fig. 35. — Plectopylis karenoriim. 

gives off a shortly descending arm ; it then 
rises obliquely for a short distance and finally 
bifurcates, the lower arm of the bifurcation being 
the longer, and obliquely descending, while the 
upper arm is slightly curved backwards ; the 
single arm first mentioned has posteriorly at its 
lower termination a short obliquely descending 
ridge, and a little higher up anteriorly a stronger 
obliquely ascending ridge, while the lower arm 
of the bifurcation has posteriorly at its lower 
termination a short obliquely descending ridge, 
(see fig. 35a). Below this complicated plate 
there is a free, thin horizontal fold close to the 
lower suture, also united to the ridge at the 
aperture (see also fig. 35&, which shows both 
armatures from the side of the aperture, and 
fig. 35(-, which gives their posterior view). The 
palatal armature consists of: first, a thin and long 
horizontal fold parallel with and near the suture ; 
secondly, another thin but shorter fold which at 
first proceeds horizontally, then suddenly deflects 
posteriorly with a slight curve backwards, a small 
denticle occurring posteriorly in a line with the 
main horizontal portion ; thirdly, a short, some- 
what stouter, crescent-shaped fold, with its concave 
side facing the aperture and lower suture ; fourthly, 
a strong vertical fold, with two minute denticles 
posteriorly near its lower end ; and fifthly, a thin 
horizontal fold, slightly reflexed in the middle 
(see fig. 35(f, which shows the inside of the outer 
wall). The specimen figured is in the collection 
of Mr. Ponsonby ; it measures 13-5 millimetres 
in diameter. 

In looking over the specimens of Plectopylis of 



the McAndrew collection in the University Museum 
of Zoology, Cambridge, I found three specimens 
labelled Plectopylis burmani, Benson, doubtless a 
misspelling for P. burmanica, one of Mr. Benson's 
MS. names. On comparing them with Plectopylis 
karenorum, I found them to belong to that species. 
As I have reason to think that P. hayenorum exists 
in some collections under the name of P. burmanica, 
and as, moreover, this MS. name was never, to 
my knowledge, published by Mr. Benson, I have 
thought it useful to make mention of the above 
fact. 

Plectopylis laomontana (figs. ^&a-c), from Laos, 
was described by Dr. Pfeiffer in the " Proceedings 
of the Ecological Society," 1S62, p. 272, and 
figured by him in " Novitates Conchologicae," ii., 
t. 57, ff. 7-9 (1863). It was also figured in 
Mouhot's " Travels in the Central parts of Indo- 
china (Siam), Cambodia, and Laos," ii. (1864), 
figs. 9 and 10. As the armature has not hitherto 
been figured, I am pleased to have had the oppor- 
tunity of doing so. The shell is solid, disk-shaped, 
with the apex scarcely raised above the flattened 
spire, chestnut brown, finely ribbed above, 
smoother below, with scarcely any trace of spiral 
sculpture. It is composed of six or six and a-half 
whorls, the last of which widens rather suddenly, 
descends abruptly and shortly in front, and is 
slightly constricted behind the peristome, which 
is whitish, thickened and reflexed, and has its 
margins united by the raised, slightly curved ridge 
of the parietal callus, but a little notch occurs at 
the junctions above and below. The parietal 
armature consists of a single strong, solid lunate 
plate, with its concave side facing the aperture, 
and deflexed posteriorly below. (See fig. 36^, 
which gives the posterior view of both armatures ) 
The palatal armature consists of : first, a short 
horizontal fold near the suture ; secondly, a stouter 






a be 

Fig. 36. — Plectopylis laomontana. 

and somewhat longer horizontal fold, shortly 
bifurcated posteriorly, the upper arm proceeding 
horizontally, and the lower and shorter one 
descending obliquely ; thirdly, a shorter stout fold 
which proceeds at first nearly horizontally, then 
deflects a little about the middle, the anterior half 
being a little indented ; fourthly, a short, stout, 
straight fold, descending a little obliquely pos- 
teriorly, and also a little indented in the anterior 
half ; fifthly, another straight, short, stout fold, also 



SCIENCE-GOSSIP. 



246 



descending a little obliquely posteriorly, strongly 
indented in the middle ; sixthly, two short, stout, 
slightly oblique folds, the posterior a little 
higher than the anterior one ; seventhly, a 
short and thinner horizontal fold near the 
lower suture, with an elongated tooth a little 
above (see fig. 36^, which shows the inside of the 
outer wall with its palatal folds). The large form 
of this species, which is regarded as the type, I have 
been unable to obtain ; it is said to measure 32 
millimetres in diameter, and to show all the palatal 
folds through the shell-wall. A small variety, 
stated by Dr. Pfeiffer not to show the palatal folds 
externally, measures 21 millimetres. The specimen 
figured, which is from Louang Prabang, Laos, 
measures 19 millimetres in diameter, and does not 
show the folds through the shell ; it is in Mr. 
Ponsonby's collection. A specimen in my collec- 
tion, however, measuring 21 millimetres, distinctly 
shows the folds through the shell-wall. 

Plectopylis bnicliyplccta (figs, ^"ci-f), from Moul- 
main, was described by Mr. Benson in the " Annals 
and Magazine of Natural History," (3), xi. (1863), 
p. 319, and figured in Hanley and Theobald's 
" Conchologia Indica,"' t. 57,6. yand 10 (1870). The 
armature was figured by Lieut. -Colonel Godwin- 
Austen in the " Proceedings of the Zoological 
Society, 1874, t. 74, f. S. The shell is disk-shaped, 
widely umbilicated, dull-reddish chestnut, with 



»<;f^"^>1SJ! 






c d e 

Fig- zy.—l'lt'ctopylis brachyphcta. 



amber-coloured apex, paler below, finely and 
regularly ribbed, and decussated by minute spiral 
sculpture. It is composed of six or six and a-half 
more or less convex whorls, which increase slowly, 
the last being rounded and subangulated above, 
near the suture, and shortly and abruptly descend- 
ing in front. The aperture is ear-shaped, and the 
peristome brown, strongly thickened and a little 
reflexed, its slightly converging margins being 
joined by a thickened curved ridge, which 
is slightly notched at the junctions above and 
below. A strong entering flexuous fold is given 
off from the parietal ridge, revolving over 



less than a quarter of a whorl. The parietal 
armature further consists of two strong, vertical, 
slightly curved parallel plates ; the anterior one 
has a short horizontal support posteriorly below, 
and a strong horizontal ridge anteriorly above ; 
the posterior one gives off on the posterior side two 
short supports, one above and one below. A short, 
free horizontal fold occurs below the vertical 
plates. Fig. 37^^ shows the parietal wall with its 
plates and the fold, while fig. 37/ gives the anterior 
view of both parietal and palatal armatures. The 
palatal armature consists of: first, a thin horizontal 
fold near the suture ; next, four short, broad, oblique, 
nearly parallel folds, whose lower concave sides 
face the aperture ; finally, a short thin horizontal 
fold near the lower suture. A little above the 
second fold and united to its posterior extremity 
occurs a very short straight fold, while another 
short, slight oblique fold is found between the 
posterior ends of the fifth and sixth folds. (See 
fig. 37^, which shows the inside of the outer wall 
with its palatal folds.) Figs. ],'/d-f are drawn 
from one of the type specimens from Moulmain 
in the McAndrew collection of the University 
Museum of Zoology, Cambridge, the shells having 
been lent for this purpose by Mr. S. F. Harmer, 
the Superintendent. It measures — major diameter, 
22 millimetres ; minor diameter, iS millimetres ; 
axis, 8 millimetres. Among the shells of the genus 
Plectopylis in the British Museum, I found two 
specimens in the Theobald collection, labelled 
Plectopylis clatliratula, Benson, from Balcadua, 
Ceylon. I am not aware that Mr. Benson ever 
published this name, but Dr. Pfeiffer described a 
species belonging to a different section of the 
genus, from Ceylon, under that name. As no 
species of the section to which these three shells 
belong has e\er been found in Ceylon, it is 
probable that there is a mistake in the locality, 
and it is certain that the name is wrong. 
Judging from the external resemblances to Plec- 
topylis bracliyplccta, 1 suspected that these shells 
would prove to pertain to that species, and 
having obtained permission from Mr. Edgar Smith, 
the Assistant Keeper, to open one of the shells, I 
was enabled to confirm my suspicion, for the 
armature proved to be identical with that of P. 
bracliyplccta. One of these specimens is shown in 
three different positions in figs, sja-c. It measures — 
major diameter, 22 millimetres ; minor diameter, 
18-5 millimetres; axis, S millimetres. 

(To be continueil.) 



Ekk.^ta. — Lieut -Colonel Godwin .Austen has kindly drawn 
Miy atteiitiou to the following errors : p. 205, second column, 
fifth line from top, for Henozdan, read Hengdan ; eighth line 
from top, for Kopameda, read Kopamed/.a. He also states 
that the locality given for Mr. Ponsonby's sjiecinien of 
PliXtopyHi ,stTU'(!. Sylhet, is impossible, as these species are 
very local, and one found on the summit of a range of 5,000 
feet and upwards is not likely to occur in a country like 
Sylhet, only just above the level cf the sea, 



SCIENCE-GOSSIP. 



274 



ARMATURE OF HELICOID LANDSHELLS AND NEW 

FORMS OF PLECTOPYLIS. 

By G. K. Gude, F.Z.S. 

{Contimted from page 246.) 



pLECTOPYLIS smithiana (i) (figs. ^Sa-d). I also 
found two specimens in the Theobald collection 
of the British Museum, labelled Plcdopylis brachy- 
plecta, which, in spite of some external resemblance 
to that species, presented sufficient differences to 
lead one to suspect that they were distinct, and on 
opening one of them I found that the difference in 
the armature confirmed this suspicion. In basing 
a new species upon them, I have much pleasure in 
dedicating it to Mr. Smith, whose permission to 
open the shell enabled me to investigate the 
matter. 

Plectopylis smithiana differs from P. brachyplecta in 
being darker and larger. The ribs are coarser and 






^ 



\^^^^:'<- 



Pig, 28. — Plectopylis smithiana. 

the whorls more convex ; the last whorl is not 
angulated above, and it widens more towards the 
aperture. The peristome is less thickened and 
more reflexed, and the ridge of the parietal callus 
less stout but more raised, while the umbilicus is 
wider and much more shallow. The horizontal 

(1) Plcdobylis smithiana, n. sp. (figs. 38rt-<0.— Shell dextral, 
discoid, widely umbilicated, rufous brown, coarsely and 
regularly ribbed, with scarcely visible microscopic sculpture 
above, but strongly decussated with spiral lines below, 
suture impressed. Whorls 6, convex, slowly increasing he 
last rapidly widening towards the aperture, not angulated 
above, shortly descending in front Aperture sub-triangular , 
peristome light brown, a little thickened and reflexed, the 
margins converging; parietal callus with a strongly raised 
flexuous ridge, separated from both margms of the pens- 
fome Umbilicus^ery wide but shal^iow. Parietal wall, 
with an entering flexuous horizontal fold, united to the ridge 
at the aperture, and at one-third of the circumference from 
the aperture with one crescent-shaped vertical plate, wh ch 
has two small denticles, one above and one below on the 
anterior side. Palatal folds 6, the first and sixth thin and 
horizontal, the other four short, broad and oblique.-Majoi 
diameter, 27 millimetres; minor diameter, 21 millimetres ; 
axis, 10 millimetres. -Habitat, Attarara, Burma.-Type in 
the British Museum. 

March, 1897.— No. 34, Vol. 3. 



parietal fold deflects more at the aperture and 
there is only one vertical plate (see fig. 38^), which 
is crescent-shaped, with the convex side towards 
the aperture ; on its anterior side, in place of a 
second vertical plate as in P. brachyplecta, are 
found two elongated, oblique, converging denticles, 
one above and one below. The palatal armature 
is similar to that of P. brachyplecta. Fig. 38^^, which 
shows the parietal wall, is from one of the specimens 
in the British Museum. Figs. 38^-^ are drawn 
from a specimen, labelled Attaram, obligingly 
lent to me by Miss Linter, of Arragon Close, 
Twickenham, who informs me that she received 
it from Mr. Theobald. This was also labelled 
P. brachyplecta, but I have no hesitation in referring 
it to the new species. It measures — major diameter, 
26 millimetres ; minor diameter, 21 millimetres ; 
axis, 9 millimetres. 

Plectopylis plectostoma (figs. 39a-c) was first de- 
scribed by Mr. Benson in the " Journal of the 
Asiatic Society of Bengal," v. (1836), p. 351 ; but 
from additional material received, which enabled 
him to examine the armature, he subsequently 
published an amended description ("Annals and 
Magazine of Natural History " (3), v. (i860), 
p. 247). The species appears to be of fairly 
wide distribution, for, in addition to the original 
locality, Darjeeling, Mr. G. Nevill (Handlist (1878), 
p. 71) records the following habitats: Burma — 
Bassein and Arakan ; Assam — Sylhet, Khasia 
and Naga Hills ; while Lieut. -Colonel Godwin - 
Austen mentions specimens from the Dafla Hills, 
in Assam. The shell has been figured in Reeve's 
" Conchologia Iconica," t. 129, f. 782 (1852), in 
Martini und Chemnitz's " Conchylien Cabinet," 
2nd ed. i., t. 64, ff", 19-21 (1853), and in Hanley and 
Theobald's " Conchologia Indica," t. 13, f. 2 (1870). 
The armature was figured by Lieut. -Colonel Godwin- 
Austen in the " Proceedings of the Zoological 





L 






a b c 

Fig. -^g.— Plectopylis plectostoma. 

Society," 1874. t. 73. f- 2. After looking over a 
number of shells in various collections, I found that 
two different forms, one with and one without a 
horizontal fold given off from the parietal vertical 



275 



SCIENCE-GOSSIP. 



plate, were inclnded under this name, and it became 
therefore necessary to decide which of the two 
conformed to Mr. Benson's type, the specimens of 
which I knew to be in the Museum at Cambridge. 
Through the kindness of Mr. Harmer I have now 
been able to examine the type specimens, and I am 
pleased to have an opportunity of figuring one of 
them. Although Mr. Benson's reference to the 
armature in his amended description, " lamina i 
parietali verticali, simplici, lamellis nullis munita," 
inclined me to believe that the form without the 
horizontal fold was the true P. plectostoma, the 
examination of Mr. Benson's type shells does not 
bear out this view. All the shells of the Benson 
collection labelled " Darjeeling," which are without 
doubt Mr. Benson's types of this species, belong to 
the form with the horizontal fold, and this form 
must therefore be taken as the true P. plectostoma. 
Mr. Fulton obligingly sent me twenty-five specimens 
of each form for inspection, which, in addition to 
the specimens in my own and other collections, have 
enabled me to obtain a fairly accurate idea as to 
the constancy of both forms, the differences of 
which will be discussed further on. Plectopylis 
plectostoma is sinistral, disk-shaped, more or less 
dark corneous brown, opaque, with a conical spire, 
deeply but somewhat navro'd'ly umbilicated ; it is 
composed of seven narrow, closely and regularly 
coiled whorls, which increase slowly and are a 
little rounded above and below ; the last whorl 
scarcely widens near the aperture and shortly 
descends in front. The shell is radiately 
plicate and granulated by coarse spiral sculpture 
above, and decussated below, while the cuticle 
is thick and distinctly raised into distant 
transverse plaits. Five lines of scattered hairs, 
placed on raised ridges pass round the whole 
length of the body-whorl, the first on the 
periphery, the second a little below it, the third, 
fourth, and fifth wider apart, the last being close 
to the umbilical angulation. The aperture is 
broadly ear-shaped ; the peristome is whitish or 
rufous, thickened and reflexed, the upper margin 
widely arcuate ; the raised ridge of the parietal 
callus is scarcely curved, and not perceptibly 
separated from the margins of the peristome. The 
parietal armature consists of a strong vertical 
plate which gives off anteriorly a strong, obliquely 
ascending support below and a horizontal jold 
above, slightly notched at the junction ; on the 
posterior side of the plate are found two minute 
denticles, one near the upper and one near the 
lower extremity. A single, very short, free hori- 
zontal fold is found below the plate. The palatal 
armature consists of, first, a thin, short, horizontal 
fold close to the suture ; secondly, a thin but 
longer and broader fold opposite the upper ex- 
tremity of the vertical parietal plate, slightly 
indented in the middle, with the posterior ex- 



tremity shortly reflected at an angle of loo'' ; 
thirdly, a similar shortly reflected horizontal fold, 
notched in the middle, and then suddenly deflected 
vertically ; fourthly, a short, thin, broad fold, 
which has posteriorly to it an almost vertically 
deflected short broad fold ; fifthly, a similar short 
horizontal fold, which has also posteriorly a short, 
broad, descending fold, a little more oblique than 
the previous one ; and sixthly, a very short and 
narrow horizontal fold near the lower suture, 
situate below the space between the two preceding 
series. Fig. 3g(f is from one of the type speci- 
mens ; it measures, major diameter, 9 millimetres ; 
minor diameter, 8 millimetres ; axis, 5 millimetres. 
Two other of these specimens measure 8' 5 
millimetres, and one 8 millimetres in diameter. 
Fig- 39^1 showing the parietal wall with its 
armature by itself, and fig. 39^, showing the 
inside of the outer wall with its palatal folds, 
are from a specimen in my collection, 
from the Khasia Hills ; it measures — major 
diameter, 8'5 millimetres ; minor diameter, 725 
millimetres; axis, 45 millimetres. The specimens 
of this form submitted to me by Mr. Fulton, all 
from the Khasia Hills, range from 8 to g milli- 




Fig. 40. — Plectopylis pUctustoma var. tricarinata. 

metres in diameter. An immature specimen in my 
collection has the armature complete, as in the 
full-grown specimens, but the palatal folds are a 
little shorter ; traces of the previous palatal folds, 
one quarter of a whorl further back, can distinctly 
be seen through the shell-wall. 

Plectopylis plectostoma var. tricarinata (i) (figs. 40a 
and b). A tablet in the McAndrew collection con- 
tains five specimens, labelled "Plectopylis plectostoma, 
Bengal, Benson coll.," two of which are distinct 
from the type and appear to be worthy of a varietal 
name. Besides being larger and more conical than 
the type, they are also distinctly keeled at tiie 
periphery and have three distinct raised ridges on 
the upper side, revolving as far as the fourth 
whori. I name this form Plectopylis plectostoma var. 
tricarinata. The entire shell is shown, enlarged, 
in fig. 40a, while a portion of the last whorl, more 
enlarged, is shown in fig. 40&. The armature is 
identical with that of the type. 

(') Plectopylis plectostoma var. tricarinata, n. var. (figs. 40a 
and b), difJers from the type in being larger, in having the 
periphery acutely keeled, and in having three raised ridges 
between the periphery and the suture, revolving as far as 
the fourth whorl. — Major diameter, 10 millimetres; minor 
diameter, g millimetres ; a.xis, 6 millimetres. — Habitat, Bengal. 
— Type in the McAndrew collection of tlie University 
Museum of Zoology, Cambridge. 



SCIENCE-GOSSIP. 



276 



Plectopylis affinis (i) (figs. j,\a-d), from the Khasia 
Hills, has hitherto been confused with Plectopylis 
phctostoma, but it differs in being larger and much 
paler in colour, in having four instead of five rows 
of hairs, which are not placed on raised ridges as in 







c d 

Fig. 41. — P!ecfopylis affinis. 

that species ; the cuticle is much thinner and not 
plaited, while the spiral sculpture is less coarse 
above and scarcely perceptible below, where the 
shell is also more shining than in P. phctostoma. 
The shell is translucent and the armature is 
distinctly visible through its wall, while the 
aperture is more narrowed laterally and the upper 
margin of the peristome is less arcuate, being a 
little inflected. The umbilicus is also wider and 
scarcely angulated, while the base is much more 
flattened. The ridge of the parietal callus is 
more raised and more curved. The parietal 
armature consists of a vertical plate with 
a very short support anteriorly at the upper and 
lower extremities, but without the horizontal fold 
above as in P. plectostoma. The two denticles on 
the posterior side are larger and more elongated, 
and below the vertical plate are two short, thin, 
horizontal folds in a line with each other (see 
fig. ^id, which shows the parietal wall by itself; 
and fig. 4if, which shows both armatures from the 



posterior side). The palatal armature is similar to 
that of P. plectostoma, but the posterior portions of 
the third, fourth and fifth folds, instead of being 
straight and almost vertical, are crescent -shaped 
and oblique (see fig. 41&, which shows the palatal 
folds as they appear through the shell-wall) ; an 
additional semi-circular fold, posterior to but a 
little above the fifth fold, occurs in this specimen ; 
this, however, I have not observed in any of the 
other specimens. Fig 41a shows the entire shell 
enlarged. My specimens were obtained from Mr. 
Fulton some years ago ; the twenty-five further 
specimens from the same locality, sent to me for 
inspection by him, range from g to 11 millimetres in 
diameter. Two immature specimens in my collec- 
tion are composed of five and a-half whorls ; one of 
these has the immature barriers complete, but the 
palatal folds are very short and the posterior oblique 
portions of the fourth and fifth folds are almost 
straight instead of crescent-shaped ; externally a 
slight trace of previous folds can be discerned ; in 
the other specimen the last immature folds are 
similar to those of the first specimen, but the 
remains of a previous set is in a less advanced 
stage of disintegration. 

(To be continual.) 



(•) Pkctopyl's affinis. n. sp. (figs. 4i«-rf).— Shell sinistral, 
somewhat widely umbilicated, dis-k-shaped, pale vellowisit 
corneous, tranihtcent, radiately plicate, decussated by spiral 
lines above, smoother and shining below. Whorls 7, nar- 
row, increasing slowly, the last Xi'idening towards the 
aperture, and descending a little in front, rounded above, 
flattened below ; Jour lines of soft pilose hairs pass round 
the whole length of the body whorl, the first on the angulated 
periphery, the second a little below it, the third midway 
between the second and fourth, which is near the umbilicus. 
Aperture ear-shaped, elongated vertically ; peristome white, 
thickened and leflexed, upper margin a little depressed ; the 
raised//f.v«o;is ridge on the parietal callus is separated from the 
margins by a slight notch. Umbilicus deep and moderately 
wide. The parietal armature consists of a vertical plate witli 
two short supports anteriorly, one above and one below, 
and two elongated denticles posteriorly, one above and one 
below ; two free, short, horizontal folds in a line occur below 
the vertical plate. The palatal armature is composed of six 
folds, the first and sixth short, thin and horizontal, the 
others longer and broader ; the second a little indented in 
the middle, with the posterior termination raised obliquely; 
the third is notched in the middle, and deflects obliquely 
posteriorly ; the fourth and fifth are in two series separated 
by a short space, the anterior portion straight and hori- 
zontal, the posterior portion crescent-shaped and obliquely 
descending.— Major diameter, iomillimetres;minordiameter, 
9 millimetres; axis, 5-5 millimetres.— Habitat, Khasia Hills, 
Assam. — Type in my collection. 



300 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Section of Plectopylis. 

By G. K. Gude. F.Z.S. 
(Continued from page 276 ) 



"DEFORE resuming the consideration of other 
Burmese and Indian species of Plectopylis, I 
will deal with a small section of the genus 
characterized by a thin and transparent shell 
and a peristome with straight, acute edges. 
Two species only have hitherto been known, 
P. clathratula, from Ceylon, and P. retifera, from 
India ; but a third undescribed form, also from 
India, has been communicated to me by Colonel 
Beddome : two species from Ceylon, described and 
figured by Dr. F. Jousseaume in the " Memoires de 
la Societe Zoologique de France," vii. (1894), 
pp. 277 and 278, t. 4, ff. I and 8, have been referred 
by him to Plectopylis, and, if correctly thus referred, 
they will doubtless be found to belong to this 
section, for which I propose the name Austenia, in 





c d 

Fig. 42.— Plectopylis clathratula. 

honour of Lieut. -Colonel Godwin-Austen, who has 
contributed so largely to our knowledge of the 
genus. 

Plectopylis clathratula (figs, ^za-d), from Ceylon, 
was described by Dr. Pfeiffer in the " Zeitschrift 
fiir Malakozoologie," vii., (1850), p. 67. It 
was figured in Reeve's " Conchologia Iconica," 
t- 65, f. 336 (1852), in Martini und Chemnitz's 
" Conchylien Cabinet," 2nd ed., iii., t. 127, 
ff. 17-20 (1853), and in Hanley and Theobald's 
"Conchologia Indica," t. 132, ff. 1-4 (1875). Mr. 
Benson described what he thought was a new 
species, under the name of Helix puteola, in the 
"Annals and Magazine of Natural History" (2), 
xii. (1853), p. 92, but he subsequently pointed out 
its identity with Dr. Pfeiffer's species (loc. cit. (3), 
V. (i860), p. 247). It was also figured under Mr. 
Benson's name by Reeve, op. cit., t. igo.f. 1334(1854). 
Mr. G. Nevill (Hand List, p. 70) records P. clathratula, 
as in the Indian Museum, Calcutta, from Balapiat, 
Sikkim ; but I doubt the correctness of the identifica- 
tion of the specimens referred to and think they will 
probably prove to belong to the new species to be de- 
scribed in the next article as Plectopylis clathratuloides. 

April, 1897.— No. 35, Vol. III. 



As the armature of Plectopylis clathratula has never 
been figured, I am pleased to have an opportunity 
of illustrating it. The shell is somewhat lenticular, 
widely umbilicated, pale corneous, transparent, 
showing the palatal armature distinctly through 
the shell-wall. It is finely and regularly striated 
by raised ribs, which are more prominent above 
than below, it is acutely keeled at the periphery, 
and has two raised spiral ridges revolving near the 
peripherial keel and ascending as far as the second 
whorl. It is composed of 5^ slowly increasing 
whorls, a little convex above, inflated around the 
wide and deep umbilicus. The base of the shell is 
shining. The peristome is simple, straight and 
acute, the left margin being a little reflected over 
the umbilicus. The parietal armature consists of a 
single, slightly oblique, vertical plate, which is 
slightly twisted and a little notched in the middle, 
and gives off posteriorly above an obliquely 
ascending support (see fig 42(f, which shows the 
shell with part of the outer wall removed). The 
palatal armature appears to be somewhat variable, 
and consists of various denticles, arranged princi- 
pally in two horizontal series, midway between the 
periphery and the umbilicus. In the specimen 
figured, which is in Mr. Ponsonby's collection, the 
first series consists of : posteriorly, a short, strong, 
flattened vertical tooth, and anteriorly, two short, 
slight, horizontal denticles, separated by a short 
space, the second series consists of: posteriorly, 
a short, flattened, vertical tooth, a httle smaller 
than the one above it, and, anteriorly, a short, 
oblique, curved denticle. Below these two series 
is a longer, but thin, horizontal fold, coincident with 
the umbilical angulation, while above the vertical 
tooth of the first series is a minute, horizontal 
denticle, coincident with the peripherial keel. The 
specimen measures 5 millimetres in diameter. 
(Fig. 42rt shows both armatures from the posterior 
side, the anterior palatal denticles being hidden by 
the posterior teeth ; fig. 426 gives the anterior view 
of both armatures, but the posterior tooth of the 
first series is here hidden by the parietal plate ; 
fig. 42i; shows the palatal folds as they appear from 
below through the shell-wall ; all the figures are 
enlarged.) Two specimens in my collection — 
measuring, major diameter 6 millimetres, minor 
diameter 5 5, axis 3 millimetres — have the anterior 
portion of the first series, consisting of four 
horizontal denticles, the first two close together, 
the third a little smaller and further distant, and 



M 



SCIENCE-GOSSIP. 



301 



the fourth still smaller and still further distant ; 
the anterior portion of the second series possesses, 
in addition to the oblique curved denticle, a slight, 
straight, horizontal denticle. Another specimen, 
also in my collection, measuring 5-5 millimetres in 
diameter, has three horizontal denticles in the first 
series, while the second series is similar to that in 
my other two specimens. It possesses, however, in 
addition, one posterior and two anterior denticles 
of a previous set, separated from the mature set by 
a distance of i millimetre. 

Plectopylis rctifera (figs. 43«-c), from South India, 
was described by Dr. Pfeiffer in the " Proceedings 





Fig. n3.— Plectopylis rctifera. 

of the Zoological Society," 1845, p. 73, and figured 
in Reeve's " Conchologia Iconica," t. 173, f. 1170 
(1853), and in Hanley and Theobald's "Conchologia 
Indica," t. 87, ff. 8 and 9 (1872). As the armature 
has never been figured, I am glad to have an 
opportunity of doing so. The shell is convexly 
conical, narrowly umbilicated and acutely keeled ; 
it is dark corneous, translucent, finely and 
regularly plicated by raised ribs above, finely and 
closely ribbed below. The periphery has an acute, 
compressed keel, above which revolve two raised 
spiral ridges, which can be traced to the em- 
bryonal whorl, the lower one being provided with a 
fringe of coarse hairs. The shell is composed of 
6^ slowly increasing convex whorls, while the base 
is flattened and shining, a little tumid round the 
umbilicus, which is deep and narrow, suddenly 
widening at the last whorl. The aperture is sub- 
quadrate and elongated ; the peristome is simple, 
acute, scarcely reflected below. The parietal 
armature consists of a single, strong, vertical plate, 
slightly sinuate, but not notched, giving off a slight 
support anteriorly a little below the upper ex- 
tremity (see fig. 435, which shows both the parietal 
and palatal armatures from the posterior side). 
The palatal armature is distinctly visible through 
the shell-wall, and consists of two series of 
denticles, the upper series is composed of : pos- 
teriorly, a strong, short, vertical, flattened tooth, 
and, anteriorly, a minute, horizontally elongated 
denticle, in a line with the base of the posterior 
tooth ; the lower series is composed of : 



posteriorly, a smaller, flattened, vertical tooth, and, 
anteriorly, in a line with its top, a minute, horizon- 
tally elongated denticle, and, in a line with its base, 
a larger denticle, elongated obliquely. Above the 
periphery occurs, in addition, a small, horizontal 
denticle, and below the umbilical angulation a 
short horizontal fold. The two specimens figured 
are in Mr. Ponsonby's collection, and measure 6 
millimetres in diameter. The one shown in fig. 43c 
is not quite mature, the newly-formed palatal 
armature, near the aperture, consisting of only one 
horizontal and two vertical denticles. Colonel 
Beddome has obligingly allowed me to inspect a 
large series of specimens of this species from the 
Tinnevelly Hills ; of these, nine full-grown speci- 
mens possess only one set of denticles ; five not 
quite full-grown specimens possess two sets of 
denticles each, the older (immature) sets being 
complete, while the newly-formed sets consist of 
one, two, or three denticles ; four immature speci- 
mens have only one set of denticles ; ten immature 
specimens possess two sets of denticles. Of the ten 
specimens last mentioned, three have the older set 
complete and the newer set partly formed, five 
have the older set incomplete (partly absorbed) 
and the newer set complete, while, finally, the 
two remaining specimens have both sets complete. 
It may, therefore, safely be inferred that the 
older set does not become absorbed until the new 
set is completed. In a few instances I have 
observed that the two lower anterior denticles 
have become fused. 

(To be continued.) 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Species of Plectopylis. 
By G. K. Gude, F.Z.S. 

{Continued from page 301.) 



pLECTOPYLlS dathraluloides (i) (fig. ^^a-d). 

Colonel Beddome has kindly lent me for 

examination a number of shells of Plectopylis, from 

the Anamullay Hills, which appear to be unde- 




Fig. 44. — Plectopylis clathratiiloides. 

scribed, and for which I adopt the name of Plectopylis 
clathratiiloides, suggested by Colonel Beddome. It is 
possible, however, that this form already exists in 
some collections under the name of P. clathratiila ; 
for, as already mentioned in discussing that species, 
I believe the specimens referred to under that name 

(^) Plectopylis c!athrat%iloides, n.sp. — Shell depressed coni- 
cal, moderately umbilicated, pale corneous, translucent, finely 
and regularly plicated by raised ribs above, finely and 
closely ribbed and a little shining below ; whorls 5J slowly 
increasing, slightly convex, suture impressed. Periphery 
with an acute compressed keel, above which revolve 2 
raised spiral ridges, the lower provided with a fringe of 
coarse hairs. Aperture subquadrate; peristome simple, a 
little thickened. Umbilicus deep and moderately wide. 
Parietal armature, one strong, vertical, simple plate. Palatal 
armature in two series ; upper series with one posterior, 
vertical, conical tooth and one minute anterior denticle ; 
lower series, with one posterior, vertical tooth and a small 
anterior denticle; in addition, one elongated horizontal fold 
below the umbilical angulation and a small told above the 
peripherial angulation. Major diameter, 6 millimetres ; minor 
diameter, 5'5 millimetres ; axis, 3'5 millimetres.— Habitat, Ana- 
mullay Hills, India.— Type in Colonel Beddome's collection. 



May, 1897.-N0. 36, Vol. HI. U^H. 



in Mr. Nevill's Hand List as from Sikkim belong to 
this new form. Plectopylis clathratiiloides difTers from 
P. clathratula in being more elevated, in having a 
narrower umbilicus, and in being less shining and 
more tumid below, while it differs from P. reiifera 
in being less elevated and in having a wider 
umbilicus ; it is, in fact, intermediate between those 
two species. The parietal armature consists of a 
simple, strong, vertical plate, which is not notched, 
and is without supports (see fig. 44^). The palatal 
armature is in two series, the first (upper) series 
consisting of a posterior vertical tooth and a 
minute anterior denticle ; the second (lower) series 
being composed of a posterior vertical tooth and a 
small anterior denticle ; below the umbilical angula- 
tion there is, besides, an elongated horizontal fold, 
and above the peripherial angulation a small fold (see 
fig. 44&, which shows the base of the shell with the 
palatal armature visible through the shell-wall). 
The specimen figured is one of the Anamullay 
Hills specimens belonging to Colonel Beddome's 
collection. Six specimens from Madura, India, 
also in Colonel Beddome's collection, I refer to 
this new form ; four of these are immature and 
exhibit two sets of armatures, as is the case in 
immature specimens of P. retifera. 

Mr, E. R. Sykes and others have drawn my 
attention to the fact that the name Austenia, pro- 
posed by me for a section of Plectopylis {ante p. 300) 
is preoccupied. Under these circumstances it is 
necessary to re-name the section, and I therefore 
propose the name Sykesia, in honour of Mr. Sykes, 
who was the first to point out this fact. 






lO 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Species of Plectopylis. 

By G. K. Gude, F.Z.S, 

(Continued from Vol. Hi., page 332.) 



pLECTOPYLIS muspratti (i) (figs. 45^-/). With a 
number of Plectopylis kindly sent to me by 
Colonel Beddome for inspection, were three shells 
which he thought would prove to be new. Upon 
examination I found them to differ from all the 
described species, and now, therefore, publish 
this form as a new species under the above 
name, which was suggested by Colonel Beddome. 
Plectopylis muspratti in outward appearance some- 
what resembles Plectopylis nagaensis (vol. iii., p. 206, 
fig- 33). but the armature is quite different. 
The parietal armature (see figs. 45^ and d) consists 






Fig. 45.— Plectopylis muspratti. 



of a strong, vertical lunate plate, strongly deflected 
posteriorly below, the convex side towards the 

(1) Plectopylis muspratti, n. sp. (figs. 45a-/).— Shell sinistral, 
discoid, widely and deeply umbilicated, pale corneous, 
streaked transversely with dull brown ; finely striated and 
decussated with spiral lines, which are very distinct on the 
upper surface, but less so below. Suture impressed, spire 
a httle conical. Whorls six and a half, scarcely convex, 
slowly increasing, the last widening towards the aperture, 
slightly angular above, descending suddenly in front, and a 
little constricted behind the peristome. Aperture roundly 
lunate, peristome white, thickened and leflexed, margins 
converging. Parietal callus with a strongly raised flexuous 
ridge, which is separated from both margins by a little notch. 
Umbilicus wide and deep. Parietal wall with a short enter- 
ing flexuous fold united to the ridge at the aperture, becoming 
attenuated inwardly, and at one-third of the circumference 
trom the aperture, with a strong, crescent-shaped vertical 
plate, which is suddenly deflected posteriorly at the lower 
extremity ; below this, on the anterior side, occurs a very 
short, horizontal fold. Palatal folds six, horizontal, short 
the farst free, with a small denticle posteriorly ; the second, 
third, fourth, and fifth connected with each other by a vertical 
ridge, which deflects below the fifth fold posteriorly and 
terminates in a small, oblique denticle ; the sixth again free 
—Major diameter, 13 millimetres; minor diameter, 11 milli- 
metres ; axis 6 millimetres.-Habitat, Naga Hills, Assam. 
—Type in Colonel Beddome's collection. 

Tune, 1897.— No. 37, Vol. IV. 



aperture ; below, on the anterior side, is a very 
short horizontal fold ; a short, entering, flexuous, 
horizontal fold occurs at the aperture and is joined 
to the flexuous raised ridge which unites the twc 
margins of the peristome. The palatal armature 
consists of: first, a free, short, horizontal fold with 
a small denticle posteriorly ; next, four short, 
horizontal folds connected by a slight vertical 
ridge about their middle ; the posterior halves of 
the folds being thinner and slighter than the 
anterior halves; the vertical ridge is continued 
below the fifth fold, where it suddenly deflects 
posteriorly and terminates in a small oblique 
denticle ; below the fifth fold, a little nearer to the 
aperture, is found a sixth fold, which, like the first, 
is quite free (see fig. 45/, which shows the inner 
side of part of the outer wall with its palatal folds, 
and fig. 45^;, which gives the posterior view of 
the parietal and palatal armatures). 

Plectopylis macromphalus (figs. 46a and b) was de- 
scribed and figured by Mr, W. T. Blanford in the 
"Journal of the Asiatic Society of Bengal," xxxix. 
(1870), part 2, p. 17, t. 3, f. 14, and in Hanley and 
Theobald's " Conchologia Indica," t. 83, ff. 8-10. 
The armature was figured by Lieut. -Colonel 
Godwin- Austen in the " Proceedings of the 
Zoological Society." 1874, t- 73, f. i. The species 
has been recorded from the Khasia, Dafla and 
Naga Hills, in Assam. The shell is sinistral, 
widely umbilicated, light corneous, with in- 
cremental curved plicae, decussated by spiral 
lirae above, somewhat smooth and shining below 
It is composed of 4 J to 5I flattened narrow whorls, 
the last being scarcely wider, subangulate above, 
a little descending in front. The peristome is 
whitish, a little thickened and reflexed, slightly 




a I, 

Fig. 46. — Plectopylis inacroiHphaliis. 

flattened on the upper, outer margin ; the margins 
converge a little, and are joined by a thin callus on 
the parietal wall. The parietal armature (see fig. 
4Grt) consists of a strong vertical plate, which has a 
minute, slightly elongated, horizontal denticle 
posteriorly to its lower extremity. The palatal 
armature is in two series (see fig. 466, which shows 
the inside of the outer wall). Tho ?.nterior series 



SCIENCE-GOSSIP. 



II 



is composed of four short, broad, flattened, straight 
horizontal folds. The posterior series consists of 
six narrow horizontal folds, which are shorter than 
those of the anterior series ; the fourth and fifth 
are a little obliquely depressed posteriorly. The 
specimen is in Mr. Ponsonby's collection, and 
measures 6 millimetres in diameter. Two speci- 
mens in my collection also measure 6 millimetres 
in diameter. 

Plectopylis minor (figs. 47^-/), from Darjeeling, was 
described by Lieut. -Colonel Godwin-Austen in the 
"Annals and Magazine of Natural History" (5), 
iv. (1879), p. 164. As the species has never, to my 
knowledge, been figured, I have much pleasure in 
illustrating it. Mr. W. T. Blanford mentioned a 
var. minuy of Plectopylis niacromphalus in the 
" journal of the Asiatic Society of Bengal," .\xxix. 
(1870), part 2, p. iS, which is probably the same 
form. The shell is sinistral, openly umbilicated, 
discoid, hirsute, finely ribbed, decussated by spiral 
lirae above, pale corneous with equidistant trans- 
verse brown striae; the spire is a little raised, the 
suture impressed. There are five regularly coiled 






^ L^M 




Mj 



Fig. 47. — Plectopylis minor. 

whorls, the last being sub-angular at the periphery^ 
a little wider than the preceding whorl and a little 
descending in front. The cuticle is produced into 
distant, transverse, brownish, raised plaits, which 
are each provided with four coarse, deciduous 
hairs, forming four lines which pass round the 
body whorl. The aperture is lunate, flattened on 
the upper outer margin, and a little oblique. The 
peristome is white, a little thickened and reflexed ; 
the margins are connected by a slightly raised 
ridge on the parietal callus. The umbilicus is 
moderately deep and wide, but narrower than in 
Plectopylis mMyomphdus. The parietal armature 



consists of a strong vertical plate, a little deflexed 
below anteriorly, having posteriorly two minute 
denticles, one above and one below. A very thin, 
free horizontal fold occurs below the vertical plate, 
revolving as far as the parietal ridge at the 
aperture, where it becomes much attenuated (see 
fig. 47/.) ; this fold appears to be somewhat 
variable, for in a specimen in Mr. Ponsonby's 
collection, shown in fig. 47/, it is very short, 
and scarcely extends beyond the vertical plate ; 
while in another specimen, also in Mr. Ponsonby's 
collection, shown in fig. 471?, it is absent 
altogether. Lieut. -Colonel Godwin-Austen, in his 
description of the species, states: "Parietal vertical, 
lamina simple, with no distinct horizontal plica 
below it." 

The palatal armature is in two series, the 
anterior series consists of four thin horizontal 
folds, and the posterior series of six horizontal 
folds, the first of which is very minute, the next 
four a little broader and shorter than those of the 
anterior series, the fourth and fifth a little deflexed 
posteriorly, and the sixth very small and thin (see 
figs. 47^"). The specimen shown in figs. 47^-^ is 
in Mr. Ponsonby's collection, and measures— major 
diam., 5 millimetres; minor diam., 4 millimetres; 
alt. 2-5 millimetres. The one shown in figs. 
47/ and g is in my collection, while that shown 
in figs. 47/?-/ belongs to Mr. Ponsonby, who 
informs me that it was obtained from Mr. 
Hungerford, labelled, "P. plectostoma from Sik- 
kim." At first I was inclined to refer this 
specimen to Plectopylis hanlcyi, but upon further 
examination it appears to me to pertain to the 
species now under consideration ; the measure- 
ments are the same as in the specimen from 
Darjeeling. An immature specimen in my collec- 
tion, with four whorls completed, has the armature 
near the end of the fourth whorl, and identical 
with that of a mature shell, except that it is 
smaller. A specimen in Colonel Beddome's collec- 
tion, from the Naga Hills, labelled with the 
manuscript name, Plectopylis mimita, Bedd., I also 
refer to this species ; it is, however, a little 
smaller, measuring only 4 millimetres in diameter ; 
it is also a little more raised in the spire, and is 
more shining and darker. 

(To be continued.) 



36 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Form of Plectopylis. 

By G. K. Gude, F.Z.S. 

{Continiieil from page ii.) 



pLECTOPYLIS shanensis (figs. j^Sa-d), from 
■'• Burma, was described b y Dr. F. Stoliczka in the 
"Journal of the Asiatic Society of Bengal," xlii. 
(1873), p. 170, and figured in Hanley and 
Theobald's " Conchologia Indica " t. 149, ff, 8 and 9 
(1876). Lieut. -Colonel Godwin-Austen described a 
supposed new species, under the name of Plectopylis 
tyihimellaris, in the " Proceedings of the Zoological 





Fig. i^S. — Plectopylis shanensis. 

Society," 1875, p. 43, but he subsequently found it to 
be identical with the present species. ("Journal of 
the Asiatic Society of Bengal," xlviii. (1879), p. 2.,) 
Mr. Nevill in his Handlist, p. 71, records speci- 
mens from Kuengan, Pegu. As the armature 
of this shell has never been figured, I am pleased to 
have an opportunity of now illustrating it. The 
shell is sinistral, discoid, with the apex a little 
raised ; it is irregularly ribbed above and provided 
with fine spiral sculpture. There are from 6J to 7 
whorls, which are a little convex above, and rounded 
below ; the last being much widened towards 
the aperture and abruptly and deeply deflexed. 
The umbilicus is wide and deep, and the aperture 
widely lunate. The peristome is white, strongly 
reflected and thickened, and the margins are united 
by a strong raised flexuous ridge, notched above 
and below. The parietal armature consists of a 
strong horizontal median fold, revolving over nearly 
half of the outer whorl, and united to the ridge at 
the aperture, but it is free posteriorly. A short 
distance beyond it occurs a strong vertical lunate 
plate, which is deflected posteriorly below, where 
it gives off a short support ; on the anterior side of 
this vertical plate, also below, a strong horizontal 
fold is given off, extending a little over half the 
length of the median fold. A third horizontal thin 
fold, close to the lower suture, commences just 
below the vertical plate, and is united to the ridge 
at the aperture (see fig. ^8d, which shows the 
shell with the outer wall removed, and fig. 486, 
which gives the posterior view of the parietal and 
palatal armature). All three horizontal folds are 
visible from the aperture as seen in fig. 48^. 
The palatal armature is in two series : the 



anterior series consists of six thin horizontal sub- 
equal folds, while the posterior series is composed 
of nine short denticles arranged in a vertical row 
(see fig. 4Sf, which shows the inside of the outer 
wall). The specimen figured is in the British 
Museum, and measures — major diam., 19J milli- 
metres ; minor diam., 15J millimetres ; axis, 6 milli- 
metres ; it is from the Shan States. A specimen 
in the McAndrew collection in the University 
Museum of Zoology, Cambridge, labelled Plectopylis 
repercussa, proved on examination to pertain to the 
species now under consideration. It measures — 
major diam., 20 millimetres ; minor diam., 15 
millimetres ; axis, 6 millimetres. 

Plectopylis stenochila va.r. basilia Q) (figs. 49a-c), from 
Badung, Province of Hoo-Pe, was sent to me by 
Professor Oscar Boettger, of Frankfort. It has a 
more conical spire and the whorls are more flattened 
than in the type (see ante vol. iii., p. 204, f. 29) ; 
the periphery is acutely keeled, while in the type 
it is rounded. The parietal armature differs in 
having only four simple denticles anteriorly to the 
vertical plate, the second denticle being very 




Fig. ^^.— Plectopylis stenochila, var. basilia. 

minute (see fig. 49;) ; the palatal armature is 
identical with that of the type. 

Plectopylis emoriens (figs, ^oa-d), from the 
Province of Hou-Nan, China, was described by 
Mr. Vincenz Gredler in the " Jahrbuch der 
Deutschen Malakozoologischen Gesellschaft," viii. 
(1881), p. 15. Mr. Heude, in Part i of his " Notes 
sur les Mollusques Terrestres de la Vallee du 
Fleuve Bleu," published in the " Memoires con- 
cernant I'Histoire Naturelle de I'Empire Chinois " 
(1882), p. 34, considered this form to be a variety 
of Plectopylis fimbriosa. The two forms, however, 

(') Plectopylis stenochila, var. basilia, n. var., diflers from 
the type in the more conical spire, the more flattened whorls 
and the acutely keeled periphery.— Diani,, 6-y mUl^etres. 
Habitat, Badung, Province Hoo-P^, China. 



July, 1897.— No. 38, Vol. IV. 



SCIENCE-GOSSIP. 



37 



differ in many respects as indicated below, and I 
therefore follow Mr. Gredler in regarding Plecio- 
pylis emoriens as a valid species. It appears never 
to have been illustrated, for the figure given 
erroneously under this name by Mr. Tryon, 
" Manual of Conchology," second series, iii. (1887), 





BM 



m 



Fig. 50. — Ptcctopyli's i-moiifiis. 

t. 34, ff. 32-35, copied from Mr. Heude's work, is 
undoubtedly Plectopylis fimbriosa. The differences 
between the two species are given in tabulated 
form to facilitate comparison. 



Plectopylis fimbriosa : 
apical whorl ribbed ; 
strong spiral sculpture 
on the upper surface ; 
suture nut impressed ; 
whorls 6, flattened ; peri- 
phery acutely keeled ; 
fringe of coarse laciniae, 
persistent ; umbilicus very 
deep, perspective ; diam., 
13-15 millimetres. 



Plectopylis emoriens : 
apical whorl smooth ; 
spiral sculpture only 
perceptible in young 
specimens ; suture deeply 
impressed ; whorls 41^, 
rounded ; periphery ob- 
tusely angled ; fringe of 
fine liairs, deciduous ; 
umbilicus moderately 
deep; diam., 6-7 milli- 
metres. 

The parietal armature is similar to that of 
Plectopylis fimbriosa, but the palatal armature 
slightly differs, in the folds being much shorter, 
and the small tooth situated posteriorly to the 
si.xth fold in P. fimbriosa is absent in P. cmoiiens, 
and instead of it there is a minute denticle a 
little above and posteriorly to the second fold 
(see fig. 50^). The specimen figured is in my 
collection and measures 7 millimetres in diameter. 
The palatal folds are visible through the shell wall. 

Plectopylis rcserata (figs, ^la-e), from Tchen-K'eou, 
China, was described and figured by Mr. Heude in 
Part 2 of his " Notes sur les Mollusques terrestres 
de la Vallee du Fleuve Bleu " (1885), p. 112, t. 30, 
f. 3. The shell is disk-shaped, more or less 
pellucid with flattened spire, pale corneous, 
regularly and finely ribbed, decussated with very 
fine spiral lines above and below, widely and 
deeply umbilicated. It is composed of 6.^ regu- 
larly coiled whorls, which widen slowly ; the 
last whorl descends a little in front and is 
acutely keeled at the periphery, which is provided 
with a fringe of laciniae. The peristome is white, 
a little thickened and refiexed. The aperture is 
roundly lunate, the margins being united by a 
raised flexuous ridge on the parietal callus, a 



little notched above and below at the junctions. 
The parietal armature consists of a strong vertical 
lunate plate, strongly deflected posteriorly down- 
wards ; on its anterior side are found two slight, 
short, horizontal folds in a line with the upper and 
lower extremities of the vertical fold ; between 
these are two, or sometimes three, small denticles, 
elongated vertically, which in some specimens 
have coalesced (see fig. ^id, which shows part of 
the parietal wall). The palatal armature consists 
of a small, thin, horizontal fold near the suture ; 
next four stouter and longer horizontal folds united 
by a slight vertical callus, and at equal distances 
from each other ; and finally another thin, short, 
horizontal fold near the lower suture (see fig. 51^, 
which shows the inside of the outer wall). Plectopylis 
reserata is closely allied to P. laminifera (see ante, 
vol. iii., p. 205, fig. 30). It differs, however, in 
being more pellucid and less solid, in the whorls 
being flatter and in the umbilicus being much more 
shallow. The parietal armature displays consider- 
able differences ; the vertical plate is much more 
oblique downwards, and the upper and lower 
anterior folds are much thinner and shorter, while 




Fig. 51,— Plectopylis reserata. 

there are two or more denticles elongated vertically 
between these two folds, whereas in P. laminifera 
there is only one denticle, elongated horizontally, 
and this is sometimes absent. The specimen 
figured is from Patong, and is in the collection of 
Mr. Gredler, Bozen, Austria ; it measures — major 
diam., 13 millimetres; minor diam., 11 5millimetres; 
axis, 5"5 millimetres. 

{To be continued.) 



yo 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS, 

With New Species of Plectopylis. 

By G. K. Gude, F.Z.S. 

(Continued from page 37.) 



pLECTOPYLIS magna (i) (figs. 52a-/). With 
■*■ a miscellaneous collection of Plectopylis, 
from Burma, kindly sent to me by Miss 






Fig. 52. — Plectopylis magna. 

Linter, Arragon Close, Twickenham, were two 
forms which appear to be undescribed, and, 

(') Plectopylis magna, n. sp (figs. 52rt-/)'— Shell sinistral, 
solid, discoid, widely and deep'y umbilicated, horny brown, 
finely and regularly ribbed. Sutnre slightly impressed, spire 
depressed, apex scarcely raised. Whorls 7A, a little rounded 
above, tumid below, increasinu very slowly, the last widening 
a little towards the aperture, descending somewhat slowly in 
front, and a little constricted behind the peristome. Aperture 
elliptical, peristome white, thickened and reflexed, margins 
scarcely converging. Parietal callus with a raised flexuous 
ridge, separated from both margins of the peristome by a 
little notch. Umbilicus wide and deep. Parietal wall with 
a short, entering, flexuous, horizontal fold, which terminates 
at a distance of two millimetres from the parietal ridge at 
the aperture, and having at one-third of the circumference 
from the aperture two strong transverse plates ; the 
posterior one the longest, vertical, and a little flexuous, 
giving off a short, obliquely raised ridee posteriorly above, 
and a short, strong, obliquely deflexed ridge posteriorly below; 
the anterior one oblique, the upper extremity converging 
towards the posterior plate, where it gives ofl posteriorly a 
short, strong ridge, and anteriorly a strong, longer ridge, 
which becomes attenuated; at the lower extremity it gives 
off two short, strong ridges, one posteriorly and one anteriorly ; 
below these plates occurs a thin fold, close to the lower 
suture, revolving as far as the aperture, where it unites with 
the flexuous ridge. Palatal folds, 5 : the three upper 
horizontal ; the first straight and having an elongated denticle 
below it at about the middle ; the second a little deflected 
posteriorly ; the third short, crescent-shaped ; the fourth 
vertical, flexuous ; the fifth horizontal, abruptly deflexed 
anteriorly above and posteriorly below. Posteriorly between 
the first and fifth folds occur six denticles, placed vertically 
in a row, the first in a line with the elongated denticle below 
the first fold, the second a little above and the third a little 
below the second fold, the fourth in a line with the upper 
extremity, the fifth near the middle, and the sixth a little 
below the lower extremity of the vertical fold.— Major 
diameter, 22'5-25 millimetres; minor diameter, 185-21 milli- 
metres ; axis, 8 millimetres. — Habitat, Burma. — Type in my 
collection. 



although closely allied to each other and to 
Plectopylis ponsonbyi (ante vol. iii., page 178), they 
present sufficient differences to warrant their being 
regarded as distinct. Three of the specimens in 
question belong to the form which I now publish 
as a new species under the name of Plectopylis 
magna. A shell in the collection of Mr. E. R. 
Sykes, which had been labelled P. achatina, I also 
refer to this species. This new form differs from 
P. ponsonbyi in being much larger, more solid, and 
darker in colour, in having one whorl more, in the 
last whorl descending less abruptly, and in the 
whorls being more rounded. There are also 
differences in the armature, i.e. the two parietal 
vertical plates are convergent above, and the 
posterior one is considerably longer than the 
anterior one (see fig. 52e), while in Plectopylis 
ponsonbyi they are almost equal and parallel ; the 
anterior plate gives off anteriorly below a short, 
stout ridge, not a distinct fold as in P. ponsonbyi, 
and the thin fold near the suture is distinctly 
continued to the ridge at the aperture, without 
becoming attenuated ; the two upper palatal 
horizontal folds are much thinner, the third is 
short and crescent-shaped, and the vertical fold is 
not bilobed, while there are several more denticles 
posteriorly (see fig. 52/, which shows the inside of 
the outer wall). The specimen figured, received 
from Miss Linter, as above mentioned, is in my col- 
lection, and measures 25 millimetres in diameter 
A second specimen measures 22-5 millimetres in 
diameter. The third specimen is not quite mature, 
the ridge on the parietal callus at the aperture not 
being formed, but the armature is quite identical 
with that of the mature shells. Figs 52(1, b, c and e 
are natural size, figs. ^2d and/ are magnified. 
Plectopylis lissochlamys {^) (figs. 53a-/). The form 

(2) Plectopylis lissochlamys, n. sp. (figs. 53(1-/).— Shell 
sinistral, solid, discoid, widely and deeply umbilicated, 
polished, corneous, finely and regularly ribbed, decussated 
with minute spiral sculpture above. Suture impressed, 
apex a little raised, spire depressed. Whorls 7, rounded, 
increasing slowly, the last twice as wide as the penultimate, 
widening towards the aperture, but not constricted behind 
the peristome. Aperture rounded, elliptical ; peristome 
white, rather thin, reflexed ; margins a little converging. 
Parietal callus with a raised flexuous ridge separated from 
both margins of the peristome by a little notch. Umbilicus 
wide and deep. Parietal wall with a short, entering, flexuous 
horizontal fold, which runs close up to the ridge at the 
aperture, and at one third of the circumference from the 
mouth there are two rather thin transverse parallel plates, 
descending obliquely backwards, the posterior one longest and 
with a short ridge posteriorly both at the upper and the lower 
extremities ; the anterior one with a longer ridge anteriorly 
at the upper extremity, and two short but stouter ridges at 
the lower extremity, one anteriorly and one posteriorly ; 
below these plates occurs a thin horizontal fold close to the 
lower suture, becoming attenuated but distinctly perceptible 
at the aperture, where it unites with the flexuous ridge. 



August, 1897. — No. 39, Vol. IV. 



SCIENCE'GOSSIP. 



71 



received with P. magna, as above mentioned, I 
propose to distinguish as Plectopylis lissochlamys. 
Two specimens were sent to me by Miss Linter. 
Dr. von Mollendorff, the German Consul in 
Manila, Luzon, however, has obligingly sent me 
for inspection several specimens of Plectopylis, 
amongst which are two (labelled Plectopylis re/iiga) 
which I refer to this new species. Plectopylis 
lissochlamys differs from P. magna in being much 
smaller and shining, as well as paler in colour ; the 
shell in shape and texture resembling Plectopylis 
piilvinaris, which, however, is a dextral shell (ante 
vol. iii., page 180, fig. 25). It is more solid and 
darker in colour than P. ponsonbyi and it is more 
coarsely ribbed ; the two last whorls increase 
more suddenly, and the last is not constricted 
behind the peristome as is the case in P. ponsonbyi. 
The two parietal plates (see fig. 53^) are much 
thinner, and the anterior ridges of the anterior 
plate much shorter and slighter than those of 
P. ponsonbyi ; they are parallel instead of convergent 
as in P. magna. A comparison of the figures will 
indicate differences in the palatal armature. The 
specimen figured is in my collection and measures 
ig millimetres in diameter. Figs. 53^-^ are natural 
size, while figs, ^^d-f are magnified. Fig. 53^ 
shows the parietal and palatal armature from the 









Fig' 5l.—PlectopylU lissochlamys. 

posterior side ; fig. 53^ a part of the parietal wall 
with its plates ; and fig. 53/ the inside of the outer 
wall with its folds and denticles. 

Plectopylis quadrasi (figs. 54^-^) was described by 
Dr. O. F. von Mollendorff, in the " Nachrichtsblatt 
der Deutschen Malakozoologischen Gesellschaft,' 
XXV., 1893, p. 172. It was collected near the 
village of Siamsiam, in the Province of Caguayan, 
Luzon, Philippine Islands. Only three species of 
Plectopylis have hitherto been recorded from the 
Philippine Islands, viz., the species now under con- 
Palatal folds, 5 ; the three upper horizontal, thin, the first 
and second with a denticle posteriorly ; the third deflected 
posteriorly; the fourth vertical, the upper part deflexed 
anteriorly, the lower part deflexed posteriorly, with two 
denticles posteriorly, one about ihe middle and one near the 
lower extremity ; the fifth short, horizontal, indented at the 
middle, with a slight curved denticle posteriorly. — Major 
diameier, ig-20 millimetres ; minor diameter, 16-17 milli- 
metres ; axis, 5-7 millimelrc. — Habitat, Burma. — Type in 
my collection. 



sideration, and P. trocJiospira and P. polyptychia, both 
of which latter will be dealt with in a future paper. 
As Plectopylis quadrasi has never been figured, I 







Fig. 54. — Plectopylis quadrasi. 

have much pleasure in now illustrating it. The 
shell is dextral, openly umbilicated, depressed 
conical, thin, dark horny brown, regularly ribbed 
above and finely striated below. The suture is 
impressed, and the spire a little elevated. It is 
composed of six rounded whorls, which increase 
very slowly and regularly, the last not descending 
in front, keeled at the periphery, and obtusely 
angled around the umbilicus, which is deep and 
moderately wide. The aperture is diagonal, irregu- 
larly heart-shaped, and the peristome is brown, 
a little thickened and well reflexed, the margins 
being a little convergent and united by a slightly 
elevated, sinuous ridge. The parietal armature 
consists of two parallel horizontal folds, which 
extend over nearly half a whorl, the upper one 
being the strongest and united to the ridge at the 
aperture, while the lower one is thinner and dees 
not reach quite so far ; at their posterior termina- 
tions these two folds are united by a slight vertical 
ridge, which projects a little beyond the upper 
fold (see fig. ^^e, which shows the shell with the 
outer wall removed as far as the peristome). The 
palatal armature is composed of three short, 
parallel horizontal folds at one-third of the cir- 
cumference from the mouth (see fig. ^^c, which 
shows the shell with part of the outer wall re- 
moved, so as to expose the anterior view of the 
palatal folds, and fig. 54^^, which shows the entire 
shell with the palatal folds as they appear through 
the shell-wall). The two specimens figured are 
from Palanan, North Luzon, and are in my 
collection ; they measure, major diameter, 3-5 milli- 
metres ; minor diameter, 3 millimetres; axis, 175 
millimetres. All the figures are enlarged. 

(To be continued.) 



I02 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 
(Continued from page 71.) 



pLECTOPYLlS polyptychia (tigs, s^a-d), from 
-* Mount Licos, Cebu, I'hilippine Islands, was 
described by Dr. von Mollendorff in the " Jahrbuch 
der Deutschen Malakozoologisciien Gesellschaft," 
xiv. (1887), p. 272. Tiie shell was figured in the 
same volume (t. 8, f. 8) ; the armature, however, 
was not figured, and I have pleasure in illustrating 





c d 

Fig- iS.—Plectopylis polyptychia. 

it The shell is dextral, discoid, openly umbilicated, 
finely and regularly ribbed above, finely striated 
below, and horny-brown in colour. The spire is 
scarcely raised and the suture is well impressed 
There are five and a-half to si.x convex whorls, 

September, 1897.— No. 40, Vol. IV. 



which increase slowly and regularly, the last being 
angulated above the periphery _and scarcely descend- 
ing in front. The aperture is diagonal, oblique and 
heart-shaped ; the peristome is but little thickened 
and reflexed, its margins are united by a raised 
bilobed ridge at the parietal callus. The parietal 
armature consists of two parallel, horizontal folds 
revolving over one-third of the body-whorl, the 
upper strong, and united to the raised ridge at 
the aperture, which it bisects ; the lower thinner, 
not reaching quite so far at the aperture (see 
fig- 55^')- The palatal armature consists of ten to 
twelve denticles, arranged vertically in a row, eight 
of which are larger than the rest, elongated hori- 
zontally, and have one or two minute ones both 
above and below them (see fig. 551?, which shows 
the inside of the outer wall with its denticles). 
The shell figured is in Mr. I^onsonby's collection, 
and measures — major diameter, 4 millimetres ; 
minor diameter, 325 millimetres; altitude, 1-25 
millimetres. 

Plcctopylis schistoptychia (figs. 56a-c), from the 
Chinese province Hoo-Nan, was described and 
figured by Dr. von Mollendorff in the " Jahrbuch 
der Deutschen Malakozoologischen Gesellschaft, 
xiii. (1886), p. 185, t. 6, f. 2. As in the case of 



SCIENCE-GOSSIP. 



103 



the preceding species, the armature has not been 
illustrated, and I am glad to have an opportunity 
of giving figures of it. The shell is dextral, finely 
striated, and distantly ribbed above, finely striated 
and shiuing below, light coriieous, pellucid, and 
widely umbilicated The spire is a little elevated 
and the suiur'u is distinctly impressed. There 
are from six to six and a- half convex whorls, 
which increase very slowly and regularly, the 
last being carinated above the periphery, 
rounded below, slowly and shortly descending 
in front. The aperture is roundly lunate, 
oblique ; the peristome white, a little thickened 
and reflexed, its margins being connected by a 
much raised curved plate on the parietal wall. 






S] 



Fig. ^G.—Plectopylis schistopiyclna. 

slightly notched at the junctions above and below. 
The parietal armature consists of a strong vertical 
plate, having a short support posteriorly at the 
lower extremity, and two similar supports ante- 
riorly, one above and one below (see fig. 56^, which 
shows the parietal wall with its fold). The palatal 
armature consists of eight small denticles (above 
which are a fold and a minute denticle) in two 
series of four each, the lowest denticle of both 
series being smaller than the others and nearer 
together ; they are all more or less elongated, 
those of the posterior series being oblique, except 
the lowest, which is horizontal, while those of the 
anterior series are all horizontal ; above these 
denticles occurs the fold just mentioned, which 
is thin, horizontal, interrupted slightly near its 
posterior extremity, and becoming attenuated 
anteriorly, while near its posterior extremity is 
found the minute denticle (see fig. 56^, which 
shows the inside of the outer wall with its fold and 
denticles) ; these structures are visible through 
the shell-wall. The specimen figured is in the 
collection of Professor Boettger, of Frankfort, and 
measures — major diameter, 65 millimetres ; minor 
diameter, 55 millimetres; altitude, 30 millimetres. 
A second specimen measures C millimetres in 



diameter. Mr. Gredler, of Bozen, Austria, has 
obligingly sent to me for inspection two shells of 
this species which agree with the specimen here 
figured, except that one has ten instead of eight 
denticles, in two series of five each. 

Plcctupylis bifoiis (figs 57a-/), from Ta-kouan-tchen, 
China, was described and figured by Mr. Heude 
in the second part of his " Notes sur les Mollus- 
ques Terrestres de la Valle du Fleuve Bleu " (1885), 
p. Ill, t. 30, f. 2. As I have been unable to obtain 
specimens of this shell, I have been obliged to rely 
upon Mr. Heude's description and to copy his 
figures. The shell is dextral, discoid, plicately 
striate, brownish, widely umbilicated. The spire is 
depressed and the apex a little raised. There are 
six and a-hall slowly increasing whorls, which 
are flattened above and convex below, the last 
keeled at the periphery, with a laciniated fringe, 
and shortly and abruptly descending in front. 
The aperture is semicircular and the peristome 
thickened and reflexed, its margins being con- 
nected by a raised flexuous ridge which 
is notched at the junction above and below ; 
about the middle the ridge gives off an entering, 
flattened fold. The parietal armature consists of 
two vertical plates united above and below by 
horizontal folds ; below these occurs a short, free, 
horizontal fold, while another short, horizontal 
fold is found aiiteriorly ucar the upper extremity of 
the vertical plate (see fig. 571?). The palatal 
armature is composed of four oblique folds, with 
a fifth smaller one close to the lower suture (see 
fig. 57^, which gives the anterior view of both 
armatures). From the figure it appears that there 
are besides, four small denticles posteriorly to the 
palatal folds ; but no mention is made of these in 







Fig. ^y.—t'hctopylii bijuris. 
[After Heudc.) 

the diagnosis (see fig. 57/, which shows the palatal 
folds and denticles as they appear through the 
shell-wall). The measurements given are as follows 
— major diameter, 16 millimetres ; minor diameter, 
14 millimetres; altitude, 7 millimetres. 
(To be continued.) 



138 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 
(Continued from page 103.) 



pLECTOPYLIS SCHLUMBERGERI (figs. 58 
a and b), from Halong Bay and Elephant Moun- 
tain, Tonkin, was described and figured by Mr. J. 
Morlet, in the "Journal de Conchyliologie," xxxiv. 
(1886), pp. 259 and 272, t. 12, f. 2. The shell is 
dextral, discoid, solid, and widely umbilicated ; it 
is shining, brown, coarsely striated and decussated 
by spiral lines above, smooth below. The spire is 
a little raised and there are seven whorls, which 
are obsoletely keeled above, and subangulated 





Fig. ^8.—P!ectopylis schlumbergeri. {a, original; 
b, after IMorlet.) 

below ; the last whorl does not descend in front ; 
umbilicus deep, funnel-shaped. The aperture is 
ear-shaped, and the peristome is white, thickened 
and reflexed, its margins united by a sinuous raised 
ridge, which gives off about the middle, a short, 
entering, obliquely ascending fold. The parietal 
armature further consists of a vertical plate, 
with a slight denticle anteriorly near its 
lower extremity. The palatal armature consists of 
six small, narrow teeth. I do not possess a speci- 
men of this shell, and as there is only a single 
specimen of this species in the British Museum, I 
have not had an opportunity of examining the 
armature ; consequently I have been obliged to 
rely on the somewhat meagre description of Mr. 
Morlet, and upon his figure of the armature (op. 
cit. fig. 2c), which latter I have copied (fig. 58b 
giving the anterior aspect of the parietal and 
palatal armatures.) The shell is stated to measure — 
major diameter, 26 millimetres ; minor diameter, 
22 millimetres ; height, 12 millimetres ; but the 
specimen in the British Museum (fig 58^) measures — 
major diameter, ig millimetres ; minor diameter 
16 millimetres; height, 85 millimetres. In ad- 
dition to the original locality the species has been 
collected at Nuy-Dong-Nay, Tonkin (Dautzenberg 
and d'Hamonville, "Journal de Conchyliologie," 
XXXV. (1887) p. 218). 

Plectopylis jovia (figs. 59 a and b), from Halong, 
Tonkin, was described by Mr. Jules Mabille in the 
' ' Bulletin de la Societe Malacologique de France, " iv. 
(1887), p. 99. It was figured by Mr. Pilsbry in his 
" Manual of Conchology," ix. (1894), t. 40, figs. 1-4, 
from specimens forming part of the original lot 



collected by the Abbe Vathelet. It is allied to 
Plectopylis schlumbei'geri, and like that species it is, 
unfortunately, represented by a single specimen in 
the British Museum and I have in this case 
also been unable to examine the armature. Mr. 
Pilsbry's figure of the structures in question, 
however, is so good, and his description so minute, 
that I will copy both. 

" Shell depressed, discoidal, very broadly um- 
bilicated, the umbilicus regular, funnel-shaped, 
its width contained not quite two and a-half 
times in the diameter of the shell ; solid, opaque, 
obliquely striulate and decussated by sub-obsolete 
microscopic spiral lines above ; reddish under a 
(deciduous ?) yellowish-brown cuticle ; lustreless. 
Spire slightly convex, composed of seven and a-half 
very slowly increasing whorls ; the last whorl 
wider, rather strongly deflexed in front, very convex 
beneath, and obtusely subangulated around the 
umbilicus. Aperture oblique, rotund-truncate, the 
peristome well curved, strongly reflexed, its face 
white and thickened, ends joined by an elevated lobe 
of the parietal callus, from which an entering lamella 
arises extending a short distance inward. At the 
last third within the whorl it is obstructed by 
a broad, curved, transverse parietal plate, the 
convexity of the curve outward, the upper border 
of it slightly scalloped ; a minute denticle stands 
in front of the lower end of this plate. The outer 
wall bears seven plicae : the two outer small, 
parallel to the sutures ; the next to the lowest fold 





Fig. ^(j.— Plectopylis jovia. (a, original ; b, after Pilsbry.) 

very minute, situated somewhat back of the 
others ; the four median larger and directed 
obliquely across the whorl. Altitude, 13 milli- 
metres; diameter, 29-31 millimetres. It is not 
improbable that both jovia and villedaryi will prove 
to be varietal forms of schlumbergeri " (Pilsbry, 
"Manual of Conchology," viii. (1893), p. 156). 

Fig. 59&, enlarged, is copied from " Manual 
of Conchology," ix. (1S94), t. 40, f. 4. The specimen 
shown in fig. 59a is in the British Museum, and 



October, 1897.— No. 41, Vol. IV. 



SCIENCE-GOSSIP. 



139 



measures— major diameter, 30 millimetres ; minor 
diameter, 26 millimetres; altitude, 15 millimetres. 

Plectopylis villedaryi (figs. 60 a and b), from Lang- 
son and Bac-ninh, Tonkin, was described and figured 
by Mr. C. F. Ancey in " Le Naturaliste," 1888, 
p. 71, f. 2. Mr. Pilsbry has illustrated the 
armature in " Manual of Conchology," viii. (1893), 
t. 43. f. 39. which I have been obliged to copy, 
having only seen one unbroken specimen of this 
species. The shell is solid, depressed, disk- 
shaped, regularly ribbed with minute spiral 
sculpture above, the ribs being particularly con- 
spicuous in the wide funnel-shaped umbilicus. 
There are six and a-half whorls, which increase 
slowly and regularly, the last descending in front, 
very convex and subangular around the umbilicus. 
The aperture is very oblique, somewhat ear- 
shaped, and the peristome is very much thickened 
and reflexed, the margins being united by an 
elevated tongue-shaped ridge on the parietal 





Fig. ea.— Plectopylis villedaryi. (a, original b, after Pilsbry.) 

callus. A stout curved plate is given off from this 
ridge, rising obliquely (see fig. 60a). The parietal 
armature is composed of a strong vertical plate 
with two denticles anteriorly, one near the upper 
and one near the lower extremity, the upper one 
smaller, the lower one elongated (see fig. 606, 
which gives the anterior view of both armatures). 
The palatal armature consists of seven folds, the 
first small and thin, near to and parallel with the 
upper suture; the second, third, fourth and fifth 
larger, oblique ; the sixth very minute and situated 
to the rear of the others ; the seventh small, near 
to and parallel with the lower suture (see fig. Gob). 
The measurements given are : major diameter, 
20 millimetres; minor diameter, 17 millimetres; 
altitude, 9 millimetres. The shell in the British 
Museum (shown in fig. 6oa) measures— major 
diameter, 19 millimetres ; minor diameter, 16J 
millimetres ; altitude, 8 millimetres. 

Plectopylis phlyaria (figs. 6ia-c), from Tonkin, was 
described and figured, by Mr. Mabille, in " Bulletin 
de la Societe Malacologique de France," iv. (1887), 
p. 100, t. 2, ff. 1-3. Unfortunately the armature 
does not appear to have been examined by Mr. 
Mabille, for not only has he omitted to illustrate it, 
but no mention is made of it in his diagnoses, and 
to my great regret these important structures 



remain unknown to me. Not having been able 
to obtain a specimen of this species I have been 
under the necessity of copying Mr. Mabille's figures 
and description. The shell is "openly umbilicated, 
depressed discoid, thin, somewhat solid, scarcely 




Fig. di.— Plectopylis phlyaria. (After Mabille. 

shining, dull whitish under a deciduous, greyish, 
hairy cuticle, arcuately striated, and seen under 
a lens to be covered with imbricating lamellae. 
Spire fiat, apex shining, smooth, corneous. Whorls 
seven and a-half, narrow, convex, rather rapidly 
and regularly increasing, separated by a deeply 
impressed suture. The last whorl large, but little 
wider than the preceding whorl if viewed from 
above ; laterally compressed, obscurely angulated 
at the periphery, deeply descending in front, 
tortuous, a little convex beneath. Aperture half 
round, toothed, the margins connected by a trans- 
verse parietal lamina, behind which a dentiform 
callus emerges ; peristome white, thick, reflexed. 
Major diameter, 15 millimetres, minor diameter, 
13 millimetres ; altitude, 5-5 millimetres." 
(To be continued.) 



170 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 

{Continued from page 139.) 



pLECTOPYLISpseiidophis (figs. 62a-c) fromThyet- 
^ myo, Pegu, was described and figured by Lieut. - 
Colonel Godwin-Austen, in the "Proceedings of the 
Zoological Society," 1S74, p. 610, t. 74, figs. 3 and 
3(1. The shell is sinistral, disk-shaped, pale horny 
in colour, and widely umbilicated The spire is a 
little elevated, and the suture slightly impressed. 
There are seven whorls, which increase slowly and 






Fig. ■Sz.—Pleclopylis fiseiuiuplns. (((.original; 6 and c, after 
Godwin-Austen.) 



regularly ; the last whorl is subangulated above, 
rounded below, and descends rather deeply and 
suddenly in front. The aperture is rounded, and 
the peristome is thickened and reflected, the 
margins being connected by a raised flexuous ridge 
on the parietal callus, slightly notched at the 
junctions above and below. The parietal armature 
consists of a strong vertical plate, deflected 
posteriorly at the upper extremity, and giving off 
at the lower extremity an obliquely descending 
ridge posteriorly and a short horizontal fold 
anteriorly ; the vertical plate is toothed in outline 
in the upper half, the teeth intercalating with 
three of the palatal folds (see fig. 62c). A long 
horizontal fold rises close to the vertical plate 
anteriorly, revolving as far as the aperture, where 
it unites with the raised flexuous ridge ; a thin 
-slight fold runs near to and parallel with the 



lower suture (see figs. 62b and c, which shows 
the shell with part of the outer wall removed). 
The palatal armature consists of six simple short 
folds, the lowest three the longest and highest, the 
sixth much arched outwards (see fig. 62c). To my 
regret I have been unable to examine the armature 
of this species, having seen but a single specimen, 
which is in the British Museum ; this is shown in 
fig. 62a ; it measures — major diameter, 12 milli- 
metres ; minor diameter, 10 millimetres ; altitude, 
5 millimetres. Figs. 62b and c are copied from 
" Proceedings of the Zoological Society," 1874, t. 
74, figs. 3 and sa. 

Plectopylis brahtiia (figs. 6^a-c), from Brahmakhund, 
Eastern Assam, was described and figured by 
Lieut. -Colonel Godwin-Austen in the "Journal of 
the Asiatic Society of Bengal," xlviii. (1879), p. 3, 
t. I, f. 3. The shell is sinistral, disk-shaped, pale 
horny-brown, finely and regularly striated, with a 
moderately wide umbilicus. The spire is slightly 
raised, and the apex is a little elevated. There are 
seven whorls, which are slightly convex, and increase 
slowly and regularly ; the last is angular above, 
rounded below, a little constricted behind the 
peristome, and scarcely descending in front. The 
aperture is obliquely lunate, and the peristome is 
white, a little thickened and reflexed, the margins 
being connected by a scarcely raised curved ridge 
on- the parietal callus ; the ridge is notched 
at the junctions above and below. The parietal 
armature- consists of a strong vertical plate 
having a short support posteriorly above and 
below, and giving off anteriorly at the lower ex- 
tremity a short horizontal fold ; above this are two 
free longer horizontal folds, the upper one rising 
close to the vertical plate, the lower one longer 




Fig. 63.— Plectopylis I'ahma. 

and rising a little further from the vertical fold. 
A minute denticle occurs between the second and 
third horizontal folds, and a horizontally elongated 
denticle above the upper extremity of the vertical 
fold ; a very thin slight fold runs near to and 
parallel with the lower suture, uniting with the 
ridge at the aperture (see fig. 6y, which .•:-hows the 



November, 1897. — No. 42, Vol. IV. 



SCIENCE-GOSSIP. 



171 



parietal wall with its folds). The palatal arma- 
ture is in two series, the anterior one consisting of 
four elongated horizontal folds, the second and 
third being separated by a wider space than the 
others, while the posterior series is composed of 
thirteen or fourteen minute denticles arranged 
close together, some a little elongated. The shell 
figured is in the British Museum. It measures — 
major diameter, 8 millimetres ; minor diameter, 
6-5 millimetres ; altitude, 4-5 millimetres. 

Plectopylis feddeni (figs. 6A,a-d), from Prome, in 
the Pegu district of Burma, was described by Mr. 
W. T. Blanford in the " Journal of the Asiatic 
Society of Bengal," xxx. (1865), P- 75- The shell 
was figured in Hanley and Theobald's " Con- 
chologia Indica" (1875), t, 131, ff. 1-3, while 
Lieut. -Colonel Godwin-Austen has illustrated the 
parietal armature ("Proceedings Zoological Soc- 
iety " (1874), t. 74, f. 7), and as I have been unable 
to obtain a specimen, I have copied these figures. 
According to Mr. Neville's Hand List, p. 71, the 
Calcutta Museum possesses specimens from Thyet- 



the anterior side of the first vertical fold, is found 
a small denticle. Above and below there is a 
similar free horizontal fold (see fig. 64(f). The 
palatal armature consists of five folds, which are 
at first horizontal but become vertical posteriorly ; 
the first and second are longer than the rest. The 
measurements are stated to be — major diameter, 
16 millimetres; minor diameter, 13 millimetres; 
altitude, 45 millimetres. 

(To he continued.) 





'£.lli^:'!fTr?77Tn 




Fig. 6^.— Plectopylis feddeni. {a-c, after Hanley and 
Theobald ; d, after Godwin-Austen.) 



myo. The description and figures referred to 
show that the shell is sinistral, discoid, very 
widely umbilicated, thin, whitish, irregularly and 
obliquely sculptured ; the spire is plane and the 
suture impressed. There are six and a-half to 
seven narrow whorls, which increase slowly and 
regularly, and are a little convex above; the last 
is much wider, rounded at the periphery and base, 
and abruptly descends in front. The peristome 
is a little thickened and reflexed, and the margins 
are united by a raised flexuous ridge. From 
the middle of the ridge a horizontal, entering, 
interrupted fold is given off. The parietal arma- 
ture consists of three vertical folds, of which 
the posterior one is longest and free, and gives off 
posteriorly at its lower extremity a short ridge ; 
the two anterior ones are equal in length and are 
united by two horizontal folds, of which the upper 
one continues anteriorly to the ridge at the aper- 
ture, while the lower one is very short and projects 
only a little way beyond the first vertical fold ; 
between these two horizontal folds, and close to 



SCIENCE-GOSSIP. 



231 



ARMATURE OF HELICOID LANDSHELLS 
With New Species of Plectopylis. 
By G. K. Gude. F.Z.S. 

{Continued from page lyi.) 



pLECTOPYLIS secura (figs. 65a-d), from Si-lin, 
in the Chinese province Kouang-Si, was 
described by Mr. Heude in the "Journal de 
Conchyliologie," xxxvii. (1889), p. 226, and figured 
in the third part of his " Notes sur les Mollusques 
terrestres de la Vallee du Fleuve bleu " (1890), 
t. 38, f. 6. Not having been able to obtain a 
specimen of this shell, I have been obliged to rely 
upon Mr. Heude's description and to copy his 
figures. The shell is described as dextral, discoid, 
greenish horn-coloured, striated above, shining 
below, and widely umbilicated, with the spire 
flattened and the apex scarcely raised. There are 
six rounded whorls, which increase regularly, the 
last scarcely descending in front ; the aperture is 
semi-lunate and strongly oblique ; the peristome 
narrow and reflexed ; the margins are united by 
a raised flexuous ridge on the parietal wall, and 
there is an entering horizontal fold. The parietal 
armature consists of a single vertical plate, which 
appears to be a little deflected anteriorly below 
(see fig. 6^d). The palatal armature, as figured, 
appears to consist of six oblique folds, although 
the author only mentions four in his diagnosis ; the 
first fold is minute, situate near the upper suture, 
the next four stout and oblique, and the sixth 
thinner and apparently horizontal (see fig 6^d). 
The measurements given are — major diameter, 




Fig. 65. — Plectopylis secura (after Heude). 

9 millimetres ; minor diameter, 7 millimetres ; 
altitude, 4 millimetres. 

Plectopylis Icucochilus (i) (figs. 66a-e). Five shells, 
labelled " Burma," without further indication of 

{'-) Plectopylis Icucochilus, n. sp. (figs. 66a-i')- — Shell 
sinistral, rather solid, discoid, deeply and perspectively 
umbilicated, pale yellovvisli-corneous finely and regularly 
ribbed, ornamented with minute spiral sculpture. Suture 
almost linear, spire depressed, ape.x scarcely raised. 
Whorls seven to seven and a-half, a little rounded above, 
rather tumid below, increasing slowly and regularly, 
the last descending abruptly and rather deeply in 
front. Aperture roundly oval; peristome white, a little 
thickened and strongly reflexed, the margins a little converg- 
ing; parietal callus with a slightly raised flexuous ridge, 
separated from both margins of the peristome by a little 
notch. Umbilicus deep, widely perspective. Parietal wall 



locality, received by the writer, from Mr. Hugh 
Fulton, under the name of Plectopylis leiophis, proved 
upon examination to be distinct, and to belong, in 
fact, to a different group of Plectopylis. They 
represent a species — for which I propose the name 







Fig. 66. — Plectopylis leucochilus. 

Plectopylis leucochilus — allied to P. ponsonbyi, but 
differing from it in the more raised spire and in 
having a deeper and more perspective umbilicus. 
In the armature this new species differs from the 
other members of the group of P. ponsonbyi in 
having the upper parietal fold uninterrupted. 
Figs. 66a-c show the shell in three different aspects, 
natural size, while figs. 66d and e are enlarged ; the 
former shows the parietal wall with its plates and 
folds, and the latter the inside of the outer wall 
with the folds and denticles. 

Plectopylis perrierae (-) (figs, dja-f). — Two .speci- 
mens of an undescribed Plectopylis have been 

with two transverse oblique plates converging upwards, the 
posterior one rather thin, slightly sinuous, and having a short 
ridge posteriorly at the upper and lower extremities, the 
anterior one shorter, but nmch stronger and stouter, having 
an ascending ridge posteriorly above and a short stout support 
posteriorly below ; on the anterior side are found two strong 
horizontal folds, the lower stout and short and becoming 
suddenly attenuated ; the upper fold long, rather thinner, 
following the deflection of the last whorl and terminating 
close to the ridge at the aperture, but not being united to it; 
a very thin horizontal fold rises below the transverse plates 
close to the lower suture, runs parallel with it, and terminates 
at the ridge at the aperture. Palatal folds, five : the first near 
the suture, straight and nearly horizontal ; the second a little 
more oblique and deflected posteriorly ; the third nearly 
horizontal, but more deflected posteriorly ; all three have a 
slight indentation near the posterior extremity formiiig a 
bead-like termination ; the fourth is vertical, deflected a little 
anteriorly above and posteriorly below, having posteriorly a 
small denticle near the lower extremity and another about 
the nnddle ; the fifth is near the lower suture, horizontal and 
deflected at both extremities.— Major diameter, 15-17 milli- 
metres; minor diameter, 12-14 millimetres; altitude, 6-7 
millimetres.— Habitat, Burma.— Type in my collection. 

(~) Plectopylis penieme, n. sp. (figs. 67<i-/).— Shell sinistral, 
discoid, widely and deeply umbilicated, pale corneous, very 
finely and regularly striated, and decussated by spiral lines. 
Suture slightly impressed, spire flattened, apex a little raised, 
whorls si.x to seven, increasing slowly and regularly, flattened 
above, rounded below, the last angulated above the periphery 



January, iBgB. — No. 44, Vol. IV. 



232 



SCIENCE-GOSSIP. 



obligingly placed in my hands by Miss Linter, at parietal and palatal armatures from the posterior 



whose request I name it after her friend, Mrs. 




6y.~Plectopylis pen'icrai 



Lumley Perrier. In contour this new species 
resembles Plectopylis perarcta (ante vol. iii. page 155, 
fig. 19), but the shell is much larger. The 
parietal armature further connects it with the 
species just named, but the palatal armature is 
more like that of P. kiophis. The two specimens 
of the new species are stated by Miss Linter to be 
from Thayet-Mayo, Pegu, Burma ; a third specimen, 
which is in Miss Linter's collection, is accom- 
panied by a label bearing the locality, Niningo 
(Burma ?), but I have failed to trace this name in any 
of the maps and gazetteers to which I have access. 
The specimen figured, and the one in Miss 
Linter's collection, have the measurements given 
in the diagnosis, but my second specimen measures 
only 12 5 millimetres in diameter. Figs. 6'ja-c 
show the shell in three different aspects, natural 
size ; figs. 67^-/, are enlarged ; d, shows the 

and round the umbilicus, and descending shortly and 
abruptly in front. Aperture heart-shaped ; peristome white, 
scarcely thickened, a little reflected; the margins united by 
an elevated sinuous ridge on the parietal callus, notched at 
the lower junction. Umbilicus wide and deep. Parietal 
wall with a thin vertical plate, strongly deflected posteriorly 
below, and giving oft a short horizontal ridge at the upper 
extremity on each side ; a long horizontal flexuous fold 
rises close to the upper extremity of this plate on the anterior 
side, descending suddenly at first, then ascending gradually, 
and afterwards gradually descending, following the deflection 
of the last whorl, becoming united to the ridge at the 
aperture ; a second, shorter, horizontal fold occurs below 
this one, rising close to the lower extremity of the vertical 
plate, proceedmg horizontally at first, and then ascending a 
little ; another very thin fold rises below the vertical plate, 
running parallel to the lower suture as far as the aperture, 
where it unites with the ridge. Palatal folds, five : the first, 
rather long and thin, near to and parallel with the suture, 
with a deep indentation near the posterior extremity, divid- 
ing it into two unequal parts; the second, horizontal, a 
little deflected posteriorly, with an elongated denticle 
posteriorly, an 1 a second, smaller, one above the first ; the 
third fold much shorter, strongly curved downwards 
posteriorly, with a minute denticle posteriorly; the foiirth 
fold vertical with an obliquely descending ridge posteriorly 
at the upper extremity, and bifurcated at the louer extremity, 
the anterior aim of the bifurcation the shorter; a minute 
denticle occurs near the ridge at the upper extremity and a 
second one near the middle, both on the posterior side ; the 
fifth fold is thin, horizontal, and strongly deflected on both 
sides. — Major diameter, 15 millimetres; minor diameter, 
12 milliuietres ; altitude, 5 millimetres. — Habitat, Thayet- 
Mayo, Pegu, Burma. — Type in my collection. 



side ; e, the inside of the outer wall with the 
palatal folds and denticles ; and /, the parietal 
wall with its plate and folds. 

(To be continued.) 



SCIENCE-GOSSIP. 



263 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Species of Plectopylis. 

By G. K. Gude, F.Z.S. 

[Continued from page 232.) 



pLECTOPYLIS OGLEI (figs. 68a-//), from 
Sadiya, Assam, was described and figured 
by Lieut. -Colonel Godwin-Austen in the "Journal 
of the Asiatic Society of Bengal," xlviii. (1879), 
p. 3, t. I, f. 2. The shell is dextral, disk-shaped, 
widely umbilicated, corneous, marked transversely 







Fig. 68.~Plfctopylis oglei. 

with dark brown, finely and closely striated, the 
upper side coarsely decussated with raised spiral 
lines. The spire is scarcely raised, the apex a 
little elevated, and the suture impressed. There 
are eight rounded whorls, which increase slowly 
and regularly, the last being angular above and 
below, and obsoletely keeled at the periphery, 
descending slowly in front. The aperture is 
oblique, roundly ovate, slightly depressed above ; 
the peristome is white, thickened and reflexed, its 
margins are connected by a scarcely raised curved 
ridge on the parietal callus, a slight notch being 
observable above and below at the junctions. The 
parietal armature consists of a single strong 
vertical plate, which gives off posteriorly two short 
ridges, one at the upper and one at the lower 
extremity (see fig. 68^, which gives an enlarged 
view of a specimen with the outer wall removed). 
The palatal armature consists of six horizontal folds : 
the first, near the suture, very short and thin ; the 
second, third, fourth, fifth, and sixth, bilobed 
or bisected about the middle, where a slight 
vertical ridge connects their posterior portions ; 
the posterior portion of the second fold is sinuous, 

February, i8g8.— No. 45, Vol. IV. 



somewhat S-shaped ; the third, fourth, and fifth 
are slightly deflected posteriorly ; the sixth is very 
unequally bisected, the posterior portion being 
less than a third the length of the anterior por- 
tion, which is raised at first and then suddenly 
deflected (see fig. 680', which shows the inside 
of the outer wall of the shell enlarged). The 
illustrations have been made from the type 
specimens in the collection of Lieut. -Colonel 
Godwin-Austen, to whom I am under obligation 
for the loan of them. The specimen shown in 
figs. 68a-c (natural size) measures ; major diameter, 
27 millimetres ; minor diameter, 25 millimetres ; 
altitude, 8 millimetres; figs. 68e-g (enlarged), are 
taken from a specimen not quite full-grown ; 
e shows the parietal and palatal armatures from 
the anterior side ; /, their posterior aspect ; and g, 
as just mentioned, the inside of the outer wall with 
its folds. This specimen exhibits the remains of a 
previous parietal plate, one quarter of a whorl 
behind the permanent one. Fig. <58/j, shows the 
inside of a portion of the outer shell-wall of the 
specimen shown in fig. 68d, the armature of which 
is incomplete, a portion having been broken away. 
Two immature specimens in different stages of 
growth exhibit armatures identical in all respects 
with those illustrated, except that the palatal folds 
are less bilobed. The species under consideration 
is allied to Plectopylis serica, but it is larger, and 
presents considerable difterences in the palatal 
armature. 




Fig. 69. — Plectopylis munipiirensis. 

Plectopylis inunipurciisis (figs. 69^-^), from the 
Ihang Valley, Munipur, was described and figured 
by Lieut. -Col. Godwin-Austen in the " Proceedings 
of the Zoological Society," 1874, p. 610, t. 73, f. 6. 



264 



SCIENCE-GOSSIP. 



The shell is dextral, disk-shaped, deeply and rather 
widely unbilicated, pale ochreous brown, irregularly 
marked with a darker shade, regularly and finely 
striated, with many raised spiral ridges. The 
spire is depressed-conical, the apex prominent, and 
the suture slightly impressed. There are seven 
whorls, flattened above and tumid below, the last 
scarcely descending in front. The aperture is 
oblique, a little depressed above, somewhat ear- 
shaped ; the peristome is white, a little thickened 
and reflexed, its margins being united by a strong, 
raised, curved ridge on the parietal callus, and 
notched above and below at the junctions. The 
parietal armature consists of a single, strong, 
vertical plate, which is obliquely deflected towards 
the aperture ; it has two slight supports posteriorly 
— the lower a little deflected, the upper obliquely 
raised — and gives off anteriorly, at the upper 
extremity, a long, slightly raised ridge ; a minute 
denticle occurs just below the vertical plate (see 
fig. 6gd, which gives an enlarged view of the shell 
with a portion of the outer wall removed). The 
palatal armature consists of six more or less 
horizontal folds : the first very minute near the 
suture ; the second long and descending a little 
obliquely towards the middle, with the posterior 
end suddenly raised ; the third and fourth also 
descending a little obliquely, their posterior ex- 
tremities dilated, almost bifurcated ; the fifth 
also descending a little, its posterior termination 
suddenly deflected ; the sixth, horizontal, with a 
minute denticle above, and an elongated one a 
little further back, below the posterior termination 
of the fold (see fig. 69^, which shows the inside of 
the outer wall of the shell). The figures are taken 
from the type specimens in the collection of Lieut. - 
Colonel Godwin-Austen, who has obligingly lent 
them to me for this purpose. The shell measures: 
major diameter, 10-5-11 millimetres ; minor 
diameter, 9-95 millimetres ; altitude, 5 millimetres. 
Figs. 6ga-c are of natural size, while figs. 6gd-g 
are enlarged ; e shows the armatures from the 
anterior and/ from the posterior side. 

Plectopylis blanda (i) (figs, joa-f). A single speci- 



men received by the writer under the name of 
Plectopylis minor, from the Naga Hills, was sent 
to Lieut. -Colonel Godwin-Austen for examination, 
and was found by him to be a new species. It 
differs from Plectopylis minor in being larger and 
more elevated, and having a wider and deeper 
umbilicus. The parietal armature differs in 
having an additional fold above the vertical plate, 
and the anterior denticles are almost united to this 
fold. The palatal armature differs in the posterior 
folds being very short and almost reduced to 
denticles. Figs, yoa-c show the shell in three 







^ J 

Fig. yo.— Plectopylis blanda. 

different aspects. Fig. jod gives the posterior 
view of the two armatures ; e, the inside of the 
outer wall ; and /, a portion of the parietal wall, 
with its plate and folds. All the figures are 
enlarged. 

Erratum. — A typographical error occurs ante 
p. 231— the name Plectopylis leucochilus should read 
Plectopylis leucochila. 

(To be continued.) 



{}) Plectopylis blanda, n. sp. (figs, yoa-f). — Shell sinistral, 
depressed conical, widely and deeply umbilicated, whitish- 
corneous, finely and regularly ribbed. Spire conical, apex 
prominent, suture distinctly impressed. Whorls six, tumid 
above, rounded below, increasing very slowly and regularly, 
the last not descending in front, angulated above the peri- 
phery and round the wide perspective umbilicus. The 
cuticle is produced into deciduous hairs on the ribs, forming 
spiral rows. Aperture oblique, lunate, a little flattened on 
the upper, outer margin. Peristome white, a little thickened 
and reflexed, the margins united by a slight, flexuous ridge on 
the parietal callus. Parietal wall with a strong, vertical 
plate, slightly deflected anteriorly and having two minute 
denticles posteriorly, the upper vertically the lower hori- 
zontally elongated. A very thin horizontal fold occurs below 
the vertical plate and a very short fold above it. Palatal 
folds in two series ; the anterior consisting of six thin hori- 
zontal folds, the first and sixth a little shorter and placed a 
little further back than the other four; the posterior series 
consists of four very short folds or denticles. — Major 
diameter, 6 millimetres ; minor diameter, 5 millimetres ; 
altitude, 3 millimetres. Habitat— Naga Hills, Assam.— Type 
in my collectic.%. 



284 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS, 

With a New Form of Plectopvlls. 

By G. K. Gude, F.Z.S. 

(Continued Jioiii pat;c 264.) 



pLECTOPYLIS DIPTYCHIA (ligs. jui-J), from 
the province of Kouei-Tchou, China, was 
described by Dr. von Mollendorft in the " Jahrbuch 
der Deutschen Malakazoologischen Gesellschaft," 
xii (1S85), p. 390, and the shell was figured in the 
same work, t. 10, f. 17. No figure of the armature, 
as far as I have been able to ascertain, has hitherto 
been published ; my readers will, therefore, be glad 
to be able to form an idea of these structures from 
the accompanying figures. The shell is dextral, 
discoid, light corneous, thin, sub-pellucid, finely 
striated, decussated with microscopic spiral lines 
above, shining below, widely and deeply umbi- 
licated. The cuticle is produced into distant 
plaits, which are very prominent at the periphery. 
The spire is a little raised, and the suture is 
impressed. There are six narrow whorls, which 
increase slowly and regularly, the last is angulated 
above the periphery, rounded below, not deflected 
in front. The aperture is roundly lunate, oblique ; 
the peristome white, a little thickened and reflexed, 
the margins scarcely united by the parietal callus, 
which is devoid of any ridge at the aperture. The 
parietal armature consists of two strong vertical 
plates, slightly converging above ; the anterior one 
curved, with the convex side towards the aperture, 
giving off anteriorly at the upper extremity a short 
horizontal ridge, and being a little deflected 









d 6 i 

Fig. 71. — PUitopylis diptychia. 

posteriorly below. The posterior one is crescent- 
shaped, strongly deflected posteriorly below (see 
fig. 71/, which shows the parietal wall of the shell 
with its two plates). The palatal armature is 
composed of six short, more or less horizontal 
folds; the first \ery minute, near the suture; the 
second, third, fourth and fifth obliquely deflected 
posteriorly ; the sixth horizontal (see fig. yic, 
which shows the inside of the outer shell-wall with 
its folds). The specimen figured measures : major 



diameter, 6 millimetres ; minor diameter, 5 milli- 
metres ; altitude, 3 millimetres. It was sent to me 
by Dr. von Mullendorft, and is now in my collec- 
tion. All the figures are enlarged. 

Piedopylis muiata (figs. 72(1 and b), from Tchen- 
K'eou, China, was described and figured by Mr. 
Heude, in Part 2 of his " Notes sur les Mollusques 
terrestres de la Vallee du Fleuve Bleu " (1S85), 
p. 112, t. 30, f. I. The shell is dextral, discoid. 




a b 

Fig. 72. — Plcctupylis niunita. 

light corneous, finely striated and decussated with 
microscopic spiral lines above, smooth and shining 
below. On the upper side, the cuticle is produced 
into distant persisting plaits, which form a coarse 
fringe around the periphery. The spire is a little 
elevated, and the suture linear. There are five 
and a-half to six whorls, which increase regu- 
larly, and are flattened above and rounded below ; 
the last does not descend in front, and is 
keeled at the periphery. The aperture is 
rounded, oblique ; the peristome white, a little 
thickened and reflexed, its margins being united 
by a slight ridge on the parietal callus ; the 
umbilicus is wide and deep. The parietal armature 
is similar to that of Piectopylis stenochihi (see my 
note in this series of papers, Science-Gossip, N.S., 
Vol. iii. p. 204, figs. 291!' and (^),and is as variable as 
in that species. The number of denticles in front 
of the vertical plate in Piectopylis inuiata varies 
from one to three, or such denticles may be absent 
altogether, while the upper and lower short hori- 
zontal folds in front of the vertical plate, may be 
reduced to denticles. The palatal armature is 
also similar to that of Piectopylis stcnochila (ioc. 
tit. figs. 2gc and (/), to which species the present 
one is closely allied, but the shell is more 
depressed, and the whorls are flattened above 
with the base shining and translucent, while 
in Piectopylis stenochihi the whorls are rounded 
above with the base striated and opatjue. In the 
species under consideration there are only five and 
a-half to six whorls, and the umbilicus is more 
widened at the last whori. which is keeled ,it the 



March, it.ja.— No. 46. \'ol. IV. 



SCIENCE-GOSSIP. 



28^ 



periphery, and the fimbriae are coarser, longer and 
more persistent. The specimen shown in figs. 72 
ii and /', from Sse-Tchuan, Chma, is one of two 
sent to me by Dr. von. Mnllendorfl ; it measures: 
major diameter, 75 milHmetres ; minor diameter 
65 millimetres ; altitude, 375 millimetres. 

Plectopylis livchuspira (figs. 73i<-t'), from Mount 
Licos, Cebu, I'hilippine Islands, was described by 
Dr. von Mollendortt in the " jahrbuch der Deuts- 
chen Malakazoologischen Gesellschaft," xiv. (18S7), 
p. 273, and the shell was figured in the same work, 
t. 8, f. 9. The armature, however, was not illus- 
trated, and 1 believe the fi,yurcs now given are the 
first which have appeared. The shell is dextral, 
widely and deeply umbilicated, depressed-conical, 
light corneous, finely ribbed above and striated 
below. The spire is conical and the suture im- 
pressed. There are six narrow rounded whorls, 
which increase slowly and regularly ; the last, 
considerably wider than the penultimate, has a 
thread-like keel at the periphery, is angulated 
round the umbilicus and does not descend in front. 
The aperture is diagonal, lunate ; the peristome 
white, a little thickened and reflexed, the margins 
being slightly convergent and united by a scarcely 
raised sinuous ridge at the parietal callus. The 
parietal armature consists of two long, parallel, hori- 
zontal folds, which revolve over nearly half a whorl, 
the upper one being the stronger and united to the 
ridge at the aperture, while the lower one is thinner 



Plectopylis tiochospiya, \-a.r.bohoknsis{}). Two speci- 
mens kindly lent to me by Rlr. Ponsonby, labelled 
with the manuscript name, "Plectopylis troclwspiiu 



Fig. y^.—PleLtopylii. tioclioipnu var. bohoUnhis. 

var. boJioliiisis (Mollendorfi)," certainly represent a 
distinct variety. They are smaller than the type, and 
the umbilicus is narrower. The armature is nearly 
identical, but the palatal folds are connected at 
their posterior terminations by a very slight trans- 
verse sinuous ridge, plainly discernible externally 
through the shell-wall. 

(To be lunltnncd.) 






d c 

Fii?- 75-—T'tectopylis tyoclwspini. 

and terminates at a short distance from the ridge ; 
a very thin, short horizontal fold occurs posteriorly 
a little below the upper fold (see fig. 73^, which 
shows the parietal wall of the shell with its folds). 
The palatal armature is composed of five short, 
thin, horizontal folds, which descend a little 
anteriorly (see fig. j^d, which shows both the 
parietal and the palatal armatures from the 
posterior side). The specimen figured is in the col- 
lection of Professor Oscar Boettger, of Frankfort, by 
whom this shell — which measures ; major diameter, 
4 millimetres ; minor diameter, 35 millimetres ; 
altitude, 2 millimetres — was obligingly lent to me. 

Plectopylis tiochospira is allied to P. qiuulntsi {ante 
p. 71, f. 54), but it is larger and much lighter in 
colour ; there are also certain difJerences in the 
armat.u.re. 



(1) Plectopylis tiocho^pira var. bvlioltiisis, n. var. (tif;. 74), 
Hitlers from the type in bein^ smalU r and having a narrower 
umbilicus. Major diameter, 3-25 millimetres ;minoi diametEi , 
,S ndllimttres; altitude, 175 mlllmetres. Habitat. Bchol 
Island, Philipi)iiie Islands. Tyjie in Mr. Ponsonby's col- 
lection. 



SCIENCE-GOSSIP. 



15 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 

(Continued from Vol. iv. p. 285^. 



A FEW more species of Plectopylis remain to be 
"^ described and figured. Their consideration 
has been delayed on account of authentic specimens 
being inaccessible to me ; in one case no figures 
have yet been published, while in another case, 
where the species is supposed to have been illus- 
trated, the figures represent another form. These 
are Plectopyiis repercussa, P. anguina, and P. rejuga, 
all described by Dr. A. A. Gould. In the present 
instalment I will discuss P. refjiga together with 
P. leiophis, which has been confused with it in some 
quarters, leaving P. repercussa and P. anguina, and 
sundry other allied species for consideration in 
future instalments of these papers. Plectopylis reper- 
cussa has recently been regarded as synonymous with 
P. achatina, but whether justly so or not, it was 



p. 99. This species has not hitherto been illus- 
trated, as the figures given by Philippi, by Reeve, 
and by Kiister were taken from the specimens in 
Cuming's collection, now in the British Museum, 
and these specimens, although labelled P. rejuga, 
are not that species, but P. leiophis, as careful 
comparison with Mr. Benson's type specimens has 
convinced me. I have been unable to obtain any 
specimens of P. refuga, and I am therefore com- 
pelled to rely upon Dr. Gould's description, 
supplemented by the notes and sketches by Dr. 
Bagg, and by the photographs now reproduced. 
Dr. Gould described the shell as " sinistrorse, 
discoid, flat above, concave below, greenish- 
corneous; whorls, six, closely coiled, thickly 
striated, the last deflexed near the aperture ; 






S {K3 



Fig. 75. — Phctopylis refuga. 



impossible for me to decide, as the type specimens 
of the former, as well as of the other two species, are 
in the possession of the New York State Museum, 
Albany, N.Y., and my request for the loan of them 
was referred to the Trustees, who decided not to let 
the specimens go out of the country. The Director, 
Dr. Merrill, however, very obligingly had the shells 
photographed and their armatures sketched for 
me. I have thus the pleasure of being able to lay 
authentic figures before my readers. I am much 
indebted to Dr. Merrill, as well as to Dr. Bagg, 
his assistant, who made the sketches and furnished 
valuable notes, which, together with the photo- 
graphs, enabled me to clear up the doubtful points 
in connection with the three species in question. 

Plectopylis refuga (figs. 75^-^), from Tavoy, Burma, 
was described by Dr. Gould in the "Proceedings 
of the Boston Natural History Society," ii. (1846), 

June, i8g8. — No. 49, Vol. V. 



suture impressed ; aperture very oblique, heart- 
shaped ; peristome white, reflexed, connected by a 
sinuous callus ; a white flexuous plate revolving in 
the penultimate whorl." He further remarks that 
" this remarkable shell is almost exactly like Helix 
carahinata. Per. [Corilla rivolii, Desh.] , except that 
it is reversed, and has no lamellae revolving within 
the outer lip." From the abo\e description it is 
impossible to know which form Dr. Gould had 
before him, as it applies equally to several distinct 
shells. 

The following notes have been communicated by 
Dr. Bagg : "Helix refuga, Gould, catalogue number, 
271 ; original number, A 562. Two earliest volu- 
tions smooth, remainder of shell very finely striate 
and hairy. Outer volution on lower side angular. 
Greater diameter nearly f inch [= 19 millimetres] ; 
smaller diameter, ^g. inch [= 14 millimetres]; alti- 



'A' /(; 



n. 



i6 



SCIENCE-GOSSIP. 



tude, g''j inch [= 4 millimetres]; length of hori- 
zontal fold at aperture, ^j. inch [= 5 millimetres]. 
Basal denticle [i.e. vertical parietal plate] cup- 
shaped." 

From figs. 75^ and e, which have been copied 
from Dr. Bagg's sketches, it appears that the 
parietal armature consists of a strong vertical 
plate which is concave posteriorly ; on the 
posterior side there are three short horizontal 
folds, the upper longest, the median shortest ; a 
short horizontal fold at the aperture is united to 
the flexuous ridge (see fig. 751;, which shows the 
parietal wall) ; while the palatal armature appears to 
consist of six folds : the first three short and hori- 
zontal ; the fourth strong, vertical, slightly indented 
about the middle; the fifth and sixth horizontal and 
thin (see fig. 75^, which gives the posterior aspect 
of both armatures). Figs, y^a-c are reproduced 
from the photographs of the type specimens, en- 
larged two diameters. Mr. W. T. Blanford has 
recorded the following additional habitats for this 
species: Pegu and Tenasserim (in "British Burma 
Gazetteer" (1879), i. p. 709). 

Plectopylis leiophis (figs, jba-c) from Thayet Myo, 
Pegu, was described by Mr. Benson in the 



^^^fe 





b c 

Fifi. yd.— PUctupylii leiophis. 

"Annals and Magazine of Natural History" (3), 
v. (iSGo), p. 246, and illustrated by Lieut. -Colonel 
Godwin-Austen in the " Proceedings of the 
Zoological Society," 1874, t. 74, fig. 2, who 
subsequently {ibid. 1875, p. 44) stated that this 
shell was identical with Dr. Gould's P. refiiga, 
basing this identification on the specimens in the 
British Museum, so labelled by Mr. Cuming. 
Upon comparing these latter with Mr. Benson's 
type specimens, obligingly lent to me by Mr. 
Harmer, of the University Museum of Zoology, 
Cambridge, I found they were certainly identicnl, 
but as already stated, the specimens in the 
British Museum were wrongly identified. They 
formed the subject of the illustrations purporting 
to represent P. refiiga in Dr. R. A. Philippi's 
" Beschreibungen und Abbildungen neuer oder 
wenig gekannter Conchylien," iii. Helix, t. 10, f. 4; 
in Reeve's " Conchologia Iconica," t. 82, f. 436, 
and in " Martini und Chemnitz, -Conchylien 
Cabinet " (2), i. t. 66, ff. 21-23. All these figures. 



therefore, must be referred to P. leiophis. This 
species was also figured in Hanley and Theobald's 
" Conchologia Indica," t. 13, f. 8. In addition to 
the original habitat, the species has been found at 
Kivadouk, and Akoutoung on the Irawady, below 
Prome (W. T. Blanford, Journ. As. Soc, Bengal, 
xxxiv. (1865), p. 75). I very mucli doubt that 
Mr. Benson was acquainted with Plectopylis refiiga, 
although Mr. Blanford believes he knew the 
species. Mr. Benson, in discussing P. leiophis (Ann. 
Mag. Nat. Hist. (3), v. (i860), p. 246), mentions, it is 
true, P. refuga var dextrorsa, but this form, as has 
already been shown, is allied to P. brachydisais 
(c.f. Science-Gossip, iii. p. 154) and is quite distinct 
from P. rejtiga and P. leiophis. A specimen in the 
McAndrew Collection, in the University Museum 
of Zoology at Cambridge, which contains Mr. 
Benson's types, is labelled P. refuga, but I refer 
this without hesitation to a form of P. achatina. 
P. leiophis is sinistral, discoid, pale rufous-corneous, 
finely and regularly striated, decussated by micro- 
scopic spiral lines on the upper surface, spirally 
wrinkled at the side and below. The spire is 
depressed, the apex raised a little above the plane 
of the other whorls, and the suture impressed. 
There are six and a-half narrow rounded whorls, 
which increase very slowly and regularly ; the last 
being angulated above the periphery, shortly and 
abruptly descending in front, widening a little 
towards the aperture, and slightly constricted 
behind the peristome. The aperture is roundly 
cordate, oblique ; the peristome white, thickened 
and reflected ; the margins converging and united 
by a raised curved ridge on the parietal callus, 
slightly notched at the lower junction. The um- 
bilicus is wide and moderately deep. The parietal 
armature consists of a strong vertical plate, 
angular above, where it gives off posteriorly an 
abruptly descending short ridge, while below it 
deflects obliquely, and on the anterior side it 
gives off a short horizontal fold ; a long free 
horizontal fold rises close to the vertical plate a 
little below its upper extremity, revolving parallel 
with the whorl as far as the aperture, where it 
unites with the ridge on the parietal callus ; 
between this fold and the lower one just referred 
to, occurs a very short, free, horizontal fold, but this 
does not appear to be constant, as it is absent in a 
specimen in Mr. Blanford's collection, while in 
an immature specimen in my collection, it appears 
as two small coalesced folds, and in this instance 
an additional elongated denticle occurs between 
it and the upper long fold ; in all the other speci- 
mens examined, however, the parietal armature is 
identical with that of the type specimen. A very 
thin, free horizontal fold rises below the vertical 
plate, running close to the lower suture, and 
terminating close to the ridge at the aperture. The 
palatal armatu'-e is composed of six folds, five 



SCIENCE-GOSSIP. 



17 



horizontal and one sub-vertical ; the first is thin, 
horizontal, parallel with and near to the suture, 
slightly indented about a third of its length from 
the posterior termination ; the second stouter and 
longer, also horizontal, slightly depressed, and 
indented near its posterior termination ; the third 
stout, horizontal, but shorter than the first, also 
indented near the posterior extremity ; the fourth, 
stout, horizontal, shorter than the third, bluntly 
triangular, the apex reflexed, and having a slightly 
elongated thin denticle posteriorly in a line with it ; 
the fifth, stout and very short, sub-vertical, obliquely 
crescent-shaped, the concave side towards the 
aperture and lower suture ; on the posterior side, 
near the lower extremity, occurs a small denticle ; 
the sixth is short, but broad, horizontal, and it has 
an elongated dentical posteriorly. The specimen 
figured is in Mr. Ponsonby's collection, and is 
from Pegu. It measures: major diameter, 13-5 
millimetres; minor diameter, 11-5 millimetres; 
altitude, 5 millimetres. Two specimens in my 
collection, from Akoutoung, are a little more raised 
in the spire and less angular above the periphery ; 
they measure 14 millimetres in diameter ; altitude, 
6 millimetres. 

An immature specimen in my collection, having 
five and a-half whorls completed, is interesting from 
the fact that it possesses the set of barriers nearly 
identical with that of mature specimens ; but the 
upper horizontal parietal fold is very short, only 
about one quarter of the length of that in old speci- 
mens, the anterior portion being absent ; the thin 
lowest fold runs as far as the aperture. As already 
mentioned, the second fold appears as two coalesced 
folds, and an additional denticle occurs between it 
and the upper fold. 

Addendum. — Plectopylis pssudophis (figs, yya 
and b). — Since writing my remarks upon this 
species (vol. iv., p. 170, f. G2), I have been fortunate 
in obtaining a specimen through the kindness of 
the Rev. R. Ashington Bullen. I am thus able to 
supplement my former notes and figures, which 
were copied from other sources, as at that time I 
had not examined the armature. ' The specimen in 
question differs from the type of P. pseiidophis, a.s 
described by Lieut. -Colonel Godwin Austen, in 
having an additional short fold between the 
long upper and the short lower parietal fold, 
resembling in this respect P. leiophis ; but as 
already stated, when discussing that species, this 
character appears to be an inconstant one. The 
palatal armature consists of: first, a short thin 
horizontal fold near the suture ; secondly, a 
longer horizontal fold, somewhat deflected pos- 
teriorly, with an additional short wedge-like fold 
attached to it, which has posteriorly, a little 
above it, a small denticle; thirdly, a shorter hori- 
zontal fold widened towards the posterior extremity, 
then suddenly attenuated and indented, and finally 



again widened a little ; fourthly, a short, slightly 
curved horizontal fold, descending a little pos- 
teriorly, also slightly attenuated and indented near 
the posterior extremity; fifthly, a crescent-shaped, 
sub-vertical fold (the concave side being towards 
the aperture and the lower suture), with a small 
denticle near its posterior extremity; and sixthly. 





Fig. yy. — Plectopylis pseiulophis. 

a longer curved horizontal fold, having its upper 
edge reflected towards the fifth fold, and possessing 
a small denticle near its posterior extremity. 

{To be continued.) 



'/, 



74 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS. 

By G. K. Gude, F.Z.S. 
(Continued from p. 17J 



pLECTOPYLIS reperaissa (figs. ySa-/), from 
Tavoy, Burma, was described by Dr. Gould in 
the " Proceedings of the Boston Society of Natural 
History," vi. (1S56), p. 11 ; but as the diagnosis is 
somewhat vague and as the species was not illus- 
trated, subsequent authors have considered it to be 
synonymous with P. achatina, from which species, 
however, it differs in outward appearance as well 
as in its armature. The shell is sinistrorse, disk- 
shaped, pale corneous, finely striated, the upper 



raised flexuous ridge, slightly notched above and 
below at the junctions. The parieta armature is 
very complicated, being of the same type as in 
Plectopylis karenomm, described and illustrated in 
this series of papers (Science-Gossip, N.S. iii. 
Feb. 1897, p. 245, f. 35). These two species, 
together with Plectopylis achatina, P. aiigitiiia and P. 
linterae, to be considered afterwards, form a distinct 
group, connected with the group of P. ponsonhyi 
by a transition form, represented by a single 










Fig. ■/i.—Plectopylis repercussa. 



side being strongly decussated by spiral lines, 
almost obgolete at the side, but reappearing in the 
umbilical region. The spire is a little raised, the 
suture linear. There are seven regularly coiled 
whorls, which increase slowly and gradually, and 
are flattened above and tumid below. The last 
whorl is tricarinated, one keel being at the periphery, 
one above, and another belov/ (in young shells these 
keels are provided with a fringe of coanse hairs) ; this 
whorl widens suddenly at the aperture, where it is 
deeply deflected. The aperture is almost horizontal, 
elliptic cordate ; the peristome white, thickened, 
and strongly reflected ; the margins united by a 

August, 1898.— No. 51, Vol. V. 



specimen as yet undescribed, received by me 
from Mr. Robert Cairns, of Hurst, Ashton- 
under-Lyne. A long, stout, horizontal median 
fold, given off at the apertural ridge, proceeds 
parallel with the last whorl for a quarter 
of the length of that whorl, when it gives off a 
shortly descending, slightly reflected arm, provided 
anteriorly at the lower extremity with a short, 
abruptly descending horizontal ridge; the fold 
then rises obliquely for a short distance, and finally 
bifurcates ; the loiver arm of the bifutcalion the shorter, 
and descending almost vertically ; it js provided 
posteriorly with a short horizontal ridge at its 



D 



SCIENCE-GOSSIP. 



75 



lower extremity ; the upper arm at first ascends 
obliquely, then proceeds horizontally close to the 
suture, and gradually attenuates. Below these 
complicated structures, there is a free, thin, hori- 
zontal fold close to and parallel with the lower 
suture, and extending from the aperture to a little 
beyond the lower arm of the bifurcation and its 
posterior support (see fig. jSe, which shows part 
of the parietal wall). At the aperture this 
fold is distinctly united to the transverse sinuous ridge 
(see fig. ySd). The palatal armature consists of: 
first, a strong long horizontal fold near the suture 
and parallel with it, as well as with the posterior 
portion of the upper arm of the parietal bifurca- 
tion, with which it terminates at the same point 
posteriorly ; secondly, a shorter, but much stronger 
and broader horizontal fold, which deflects with a 



terior half, with the concave side facing the vertical 
plate (see fig. 78/, enlarged, which shows the inner 
side of the palatal wall with its folds and denticles). 
Figs. jSg-i (also enlarged) show an immature speci- 
men of five and a-half whorls, in Mr. Ponsonby's 
collection ; the armature is almost identical with 
that of the mature specimens, but the main median 
parietal fold is very short and does not rise from 
the aperture, while the denticle in front of the lower 
part of the palatal vertical plate is very strongly 
developed, and it is united to the plate, so as 
to form a steep ridge. A second set of barriers, 
identical in every respect except in being a little 
smaller, occurs in this specimen one-quarter of 
a whorl further back. The mature specimen 
shown in fig. j8d is also in the collection of Mr. 
Ponsonby, and measures: major diameter, 31 milli- 







Fig. ■/g.— Pledopylis anguina. 



sharp curve posteriorly, having a little above its 
posterior termination, and almost in a line with its 
anterior portion, a slight elongated horizontal 
denticle ; thirdly, a very short, but strong and 
broad crescent-shaped fold, deflected at both 
extremities ; fourthly, facing the concave side of 
the last-mentioned fold, is a very strong and broad 
vertical plate, strongly inclined towards the aper- 
ture, with a much reflexed and thickened edge ; 
this plate intercalates between the two lower arms 
of the parietal armature ; on the posterior side of 
the plate and near its lower extremity occurs a 
stout little denticle, and a little lower and still farther 
back is found a slight elongated swelling, not 
amounting to a fold or denticle (yet present in all 
four mature specimens, as well as in an immature 
one, examined by me) ; fifthly, a thin horizontal fold, 
the anterior part straight, but curved in the pos- 



metres ; minor diameter, 24 millimetres ; altitude, 
9 millimetres ; while the immature specimen 
measures 17 millimetres in diameter. Three 
specimens in my collection measure respectively 
29 : 23 : 9 millimetres, 25 : 20 : 8'5 millimetres, 
23 : iS : 75 millimetres. The types of the species 
are in the New York State Museum, at Albany, 
N.Y., and are shown in figs. jSa-c, which are 
reproduced from the photograph kindly supplied 
by Dr. Merrill. The following particulars are 
taken from Dr. Bagg's notes which accompanied 
the photographs : " Helix repercussa, Gould. Bur- 
mah. Catalogue No., 236; original No., A 564. 
Major diameter, ii inch [= 28-5 millimetres]; 
minor diameter, i inch [= 22 millimetres] ; alti- 
tude, y\ inch [=8 millimetres] ; greatest diameter 
of aperture, ^^ inch [= 11 millimetres]." Dr. 
Gould states that the species was taken in the 



76 



SCIENCE-GOSSIP. 



Mergui Archipelago, but as this has never been 
confirmed it may be assumed that the collector, 
the Rev. J. Benjamin, made a mistake as to the 
locality. Mr. W. T. Blanford gives also the 
following localities : Moulmain and Tenasserim (in 
" British Burma Gazetteer," 1879, i. p. 709). 

PledopyUs anguina (figs. 79a-/), fromTavoy, Burma, 
was described by Dr. Gould in the " Proceedings 
of the Boston Natural History Society," ii. (1847), 
p. 218 ; and it was figured in Hanley and Theo- 
bald's " Conchologia Indica," t. 13, f. 7. By 
some authorities this species has been considered 
identical with P. achatina. It appears, however, 
to be perfectly distinct. The shell is sinistral, much 
flattened, discoid, varying in colour from corneous 
to dark chestnut ; below it is usually paler and 
flammulated with dark chestnut ; it is finely striated 
and decussated by microscopic spiral lines. The 
spire is depressed, the suture linear. There are five 
and a-half regularly coiled whorls, which increase 
slowly and gradually ; they are a little flattened 
above and a little rounded below. The last whorl 
is slightly angulated at the periphei-y ; it widens 
rather suddenly at the aperture, and is deeply 
deflected in front, and somewhat constricted behind 
the peristome. The umbilicus is extremely shallow ; 
in a specimen in my collection it is only i'5 milli- 
metre in depth. The aperture is nearly horizontal, 
cordate ; the peristome is livid or pale brown, a 
little thickened and much reflexed. A sinuous 
raised ridge on the parietal wall at the aperture 
connects the margins of the peristome; at the 
junctions above and below, however, there are 
slight notches. The armature is similar in most 



respects to that of P. repercussa, but it is less solid 
and heavy, the lower arm of the bifurcation on the 
parietal wall is longer than the upper, and the thin 
free horizontal fold near the lower suture is not 
united to the ridge at the aperture and does not 
proceed beyond the loiver arm of the hifiircation, as it 
does in P. repercussa. The upper fold of the 
palatal armature is much shorter than in 
P. repercussa, terminating posteriorly at the same 
point as the shorter upper arm of the parietal 
bifurcation ; the second and fifth horizontal palatal 
folds are much shorter anteriorly than in P. 
repercussa ; while the vertical palatal plate (the 
fourth) is broader, but less stout and less inclined 
towards the aperture than is the case in that species. 
The specimen shown in figs, ygd and e is from 
Moulmain, and is in my collection. It measures ; 
major diameter, 28 millimetres ; minor diameter, 
22 millimetres ; altitude, 7*5 millimetres. Mr. Blan- 
ford has also recorded the species from Tenasserim 
("British Burma Gazetteer" (1879), i. p. 709), 
while Mr. Nevill mentions Kuengan ("Hand-list," 
p. 72). Mr. Ponsonby possesses two specimens from 
Sgwagakin, Salween Valley, measuring 25 milli- 
metres in diameter. Figs. 79^-^ are reproduced 
from photographs of Dr. Gould's type specimens 
in the New York State Museum. Dr. Bagg has 
supplied the following notes respecting them : 
"Helix anguina, Gould. Catalogue No., 251; 
original No., A 558. The shell is somewhat 
banded by brownish and white alternating, but not 
in all specimens." Fig. 79/ shows the posterior 
aspect of the parietal and palatal armatures. 
(To be continued.) 



114 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS 

AND NEW FORMS OF PLECTOPYLIS. 

By G. K. Gude, F.Z.S. 
(Continued from page 76.) 



pLECTOPYLIS achatina (figs. Soa-f, Sia-d and 
■^ 82a-c), from Moulmain, Burma, was des- 
cribed by. Dr. Pfeiffer, in the " Zeitschrift fiir 
Malakozoologie," 1845, p. 86, and Mr. Benson gave 
notes on the animal, in the " Annals and Magazine 







Fig. So.—Ptectopylis achatina. 

of Natural History" (3), iv. (1859), p. 95. The 
shell was figured in Hanley and Theobald's " Con- 
chologia Indica," t. 13, f. i and 4 (the latter figure 
purporting to represent P. repercussa.) Mr. Stoliczka 
described and figured the anatomy of the animal 
in the " Journal of the Asiatic Society of Bengal," 
xl. (1871), p. 221, t. 15, f. 1-3, and Lieut. -Colonel 
Godwin-Austen, the parietal armature of the shell 
in the "Proceedings of the Zoological Society," 
1874, t. 74, f. 6. The shell is sinistrorse, disk- 
shaped, very widely umbilicated, of various shades 
of chestnut, usually paler and sometimes flammu- 
lated below, irregularly and finely striated. The apex 
is usually, but not invariably, raised slightly above 
the plane of the whorls. There are six or six and 
a-half whorls, which increase gradually, and are 
more or less flattened above and tumid below ; the 
first three and a-half are smooth or nearly so, 
while the next two are somewhat coarsely striated 
and strongly decussated by spiral lines, less dis- 
tinct on the upper side of the last whorl, obsolete 
at its side, but reappearing in the umbilical region. 
The last whorl is bluntly keeled above and sub- 
angulated at the periphery ; this whorl suddenly 
widens at the aperture where it is deeply 
deflected. The aperture is almost horizontal, 
September, 1898.— No. 52, Vol. V. E 



elliptic cordate, while the peristome is thick- 
ened and strongly reflected, livid or purplish- 
brown in colour, never white ; the margins are 
united by a raised sinuous ridge, slightly 
notched at the junctions above and below. The 
parietal armature is of the same type as that 
of P. repercussa {ante p. 74, f. 78^), but the lower arm 
0/ the bifurcation is the longer of the two (see fig. Soc, 
which shows part of the parietal wall with the 
posterior portion of its armature), and the lower 
free horizontal fold close to the lower suture does 
not reach as far as the apertural ridge, and does not extend 
beyond the lower arm of the bifurcation and its posterior 
support. Fig. 80a gives the anterior and fig. 80& 
the posterior aspect of both armatures. The 
palatal armature is also similar to that of P. 
repercussa, but the first horizontal fold is shorter 
in the present species correspondingly with the 
reduction in the upper arm of the bifurcation of 
the parietal armature, while the vertical plate is 
less strong and its edge less thickened. Plectopylis 
repercussa is, generally speaking, a more solid and 
larger shell, always lighter in colour than P. 
achatina, while its white peristome will at once 
distinguish it from the latter species. The lower 
horizontal parietal fold in P. repercussa is always 
distinctly united to the apertural ridge, whereas in 
P. achatina this fold is not visible from the aperture. 
That these characters are constant, I have reason 
to believe from having opened sixteen or eighteen 
specimens without finding any variation in these 
respects. The specimen shown in figs. 8oa and b 
measures : major diameter, 22 millimetres ; minor 






c d 

Fig. 81. — Pleciopyhs achatina juv. 

diameter, 17 millimetres ; altitude, 7 millimetres ; 
while the one shown in figs. Sod-f measures 
27 : 21 : 8 millimetres ; both are from Moul- 
main, and are in my colloctiou Another 
specimen in my collection shows no trace of 



SCIENCE-GOSSIP. 



115 



the ridge at the aperture, but is in all other 
respects like the mature shells. In figs. 8ia-^ I 
have shown an immature shell, received from Mr. 
J. E, Cooper, of Highgate ; it has only four 
whorls completed, and is only furnished with 
the posterior portion of the parietal armature 
(see fig. 8ifl), but the palatal armature is quite 
complete, though correspondingly reduced in size ; 
an earlier set of barriers is found three-quarters of 
a whorl further back ; the parietal folds of this 
set have been entirely absorbed, but of the palatal 
folds there are only three, the second and third 
horizontal, and the vertical fold ; this is shown in 
fig. 816 in situ, while its anterior aspect is given in 
fig. 81C ; the two arrows in fig. 81^ indicate the 






a ii c 

Fig. 82. — Plectopylis achatina juv. 

respective positions of the two sets of barriers. In 
the McAndrew Collection, University Museum of 
Zoology, Cambridge, is a tablet with three shells, 
labelled " Nanina lacy this, type, Benson Coll." ; but 
subsequently altered in pencil to "P. kiophis (?) " 
I refer these specimens without hesitation to 
immature forms of Plectopylis achatina ; one of them 
is shown in figs. Saa-c. This specimen has four 
and a-half whorls completed, and possesses the 
immature barriers half a whorl from the aperture. 
The parietal armature is composed of only a 
crescent-shaped vertical plate, corresponding to 
the upper and lower bifurcation of the main 
horizontal fold (see fig. Szb), while the palatal 
armature, as it is seen from the outside through 
the shell-wall, is shown in fig. 82c (enlarged) ; 
there are only three folds, i.e. the second and 
third horizontal ones, which are very short and 
deflected posteriorly, and the vertical fold, with a 
posterior ridge or support below ; the arrow in 
fig. 82a indicates the position of this set of barriers. 
The specimen measures 11 : 10 : 6 millimetres 
respectively ; the first three and a-half whorls are 
ribbed, the last whorl only showing spiral sculpture. 
The cuticle is plaited transversely, and the whorl 
is angulated above, at the periphery, and below it ; 
the periphery showing traces of a fringe of laciniae. 
Below the aperture are found some traces of 
another set of barriers. The other two specimens 
referred to measure 9-5 : 8'5 : 5 millimetres ; the 
armature is one-half of a whorl from the aperture, 
and there are traces of an older set one-quarter 
of a whorl further back ; the upper and the peri- 
pherial keels are provided with a fringe of laciniae. 
These immature specimens are very interesting 
and instractive, as they tend to indicate the 



various stages through which the armatures pass 
in their evolution from simple to complicated 
barriers. 

Mr. Stoliczka remarks (Journ. Asiat. Soc. 
Bengal, xl. (1871), p. 221) that Plectopylis achatina 
is " extremely common on all the limestone hills 
about Moulmain. Among thousands of specimens 
not one dextrorse variety was met with. The larger 
specimens I have seen measured in the longer 
diameter 35 millimetres, but specimens of half 
that size, and even smaller than that, often have 
all the appearance of being full-grown." As it 
is so abundant a species, it is not surprising 
that it is so frequently seen in collections. It is 
the most variable of all the species of Plectopylis, 
As none of the many forms has been separated, 
I venture to name a few of the more prominent 
varieties. 

Plectopylis achatina var. ohesa {}) (figs, ^la-c) is 
darker in colour than the type, being of a fuscous 
chestnut. It is more compressed and distinctly 
ribbed ; the shell is higher in proportion to the 
diameter, and the umbilicus is deeper ; the last 
whorl does not widen suddenly, and the right 
margin of the peristome is depressed, the aperture 
being consequently somewhat ear-shaped ; the 
lower side slopes from the peripherial region to 
the umbilical angulation. The armature does not 





Fig. 83. — Plectopylis achatina var. obesa. 

differ materially from that of the type, except 
that the median horizontal parietal fold does not 
quite reach the apertural ridge. Six specimens 
were received by me from Miss Linter, five 
of these being more or less decorticated. 
{To be continued.) 

[Further forms of this species will be described 
and figured next month. — Ed. S.-G.] 



(1) Plectopylis achatina var. obesa, n. var. (figs. 83rt-f), 
differs from the type in being more compressed and higlier 
in proportion to the diameter ; in the last whorl not widening 
suddenly at tlie aperture, and in tiie lower side sloping from 
the periphery to the umbilical angulation ; the right margin 
of the peristome is depressed ; the umbilicus is deeper, and 
the horizontal median parietal fold does not quite reach the 
apertural ridge. The shell is darker in colour and more 
strongly ribbed. — Major diameter, 19 millimetres; minor 
diameter, 15 millimetres ; altitude, 7 millimetres. — Habitat, 
Moulmain, Burma. — Type in my collection. 



SCIENCE-GOSSIP. 



133 



ARMATURE OF HELICOID LANDSHELLS 

AND NEW FORMS OF PLECTOPYLIS. 

By G. K. Gude. F.Z.S. 

(Continued jrom page 115.) 



'pLECTOPYLIS achatina var. infrafasciata (') 
(figs. 84«-f) is still darker than the variety 
ohesa, being of a blackish or purplish-brown. Like 
that variety it is rounded in contour, but it is larger 
and more flattened ; while the umbilicus is a little 
more shallow and the peristome more flattened and 
reflexed than in the type. The peristome is livid 
purplish in colour, the left margin being paler and 
the right margin a little inflected. A whitish or 
bluish-white band below reaches from the umbilical 
angulation to the lower suture. The armature is 
similar to that of the type, but the horizontal 
parietal fold near the lower suture is visible from 
the aperture and terminates close to the ridge. 
The specimen figured was received by me from 
Mr. Robert Cairns. Four specimens in the 
collection of Mr. E. L. Layard and one specimen 
in the McAndrew collection (the latter labelled 
" Plectopylis re/uga ") all belong to this form. The 
shell figured in Hanley and Theobald's " Con- 
chologia Indica," t. 57, f. 8 and g, and Martini 
und Chemnitz " Conchylien Cabinet" (2) i. t. 66, 
f. 28-30 (from Mergui, Burma), I also refer to 
this variety. A specimen measuring 21 milli- 
metres in diameter is in the collection of Mr. 
Cairns, who also possesses four immature shells 





Fig. S^.— l'leclopylis achatina var. infiafasciata. 

in various stages of growth, all showing sets of 
barriers similar to that of the immature Plectopylis 
achatina shown in fig. 8ia. 

(') Plectopylis achatina var. infrafasciata, n. var. (figs. 84 
a-c), differs from tlie type in being more rounded in contour, 
and in the last whorl not widening at the aperture; tlie 
umbilicus is more shallow and the peristome more flattened 
and reflexed ; the right margin is a little depressed ; the shell 
is blackish or purplish brown above, with a white or bluish 
white band below, reaching from the umbilical angulation to 
the lower suture; the peristome is purplish brown, the left 
margin being paler. — Major diameter, 22 millimetres ; minor 
diameter, 18 millimetres; altitude, 8 millimetres. — Habitat, 
Limestone Rocks, Moulmain, Burma. — Type m my collection. 

October, 1898. — No. 53, Vol. V. 



5(7-f) I 



Plectopylis achatina var. venusta (2) (figs. 85. 
is smaller than any form of P. achatina I have 
seen. It is pale yellowish-white in colour, 
flammulated with chestnut above and at the 
sides. It resembles the variety obesa in the 
deeper umbilicus, the sloping underside and ir 





Fig. 85.. 



b c 

-Plectopylis achatina var. venusta. 



the comparative height of the shell ; the median 
parietal fold does not quite reach the apertural 
ridge as in that variety, and the lower horizontal 
parietal fold is not visible from the aperture ; it 
resembles the type in the sudden widening of the 
last whorl. The peristome is livid brown, the 
right margin being a little depressed ; the left 
margin is paler. The specimen figured was re- 
ceived by me as Plectopylis pachystoma Theobald ; 
but as I am not aware that this name was ever 
published, and as I have seen other shells so 
labelled, I consider it expedient to discard the 
name altogether. A specimen in the collection of 
Dr. von Mollendorff, likewise labelled P. pachy- 
stoma, I am unable to separate from the present 
variety, although it shows no flammulation and the 
peristome is white ; in other respects it is identical. 
Plectopylis achatina var. castanca (») (figs. SGa-c) 

(2) Plectopylis achatina var. venusta, n. var. (figs. Ss^-c) 
differs from the type and the other varieties in being smaller! 
It resembles the variety obesa in the deeper umbilicus, 
in the sloping underside, in the comparative height of the' 
shell, and in the median parietal fold not reaching the 
apertural ridge, but the last wliorl widens more, as in the 
type. In colour it is pale yellowish-white, flamnnilated with 
chestnut above and at the side. The peristome is livid 
brown, the left margin paler, the right margin a little 
depressed.— Major diameter, 17 millimetres ; minor diameter, 
14 millimetres; altitude, 7 millimetres. — Habitat, Burma. 
— Type in my collection. 

(') Plectopylis achatina var. castanea, n. var. (figs. 86a-c), 
differs from the type in being smaller in diameter and pro- 
portionately higher ; it is darker in colour, being blackish- 
brown above and a little paler below. It resembles the 
variety obesa in being more romided in outline, in the last 
whorl not widening suddenly at the aperture, in the sloping 
underside, and in the median parietal fold not reaching quite 
to the apertural ridge ; the last two and a-half whorls are more 
strongly decussated above and below than in anv other form. 
An obsolete keel is visible at the periphery.— Major diameter, 
21 millimeters; minor diameter, ig millimetres- altitude, 8 
millimetres.— Habitat, Hiirma.— Tvpe in my collection. 




F 



134 



SCIENCE-GOSSIP. 



is darker than the other forms of P. achatina, 
except the variety infrafasciata, being of a blackish- 
brown above, a little paler below. It is, however, 
larger than that variety, and does not possess the 
white band below ; the umbilicus is also much 
deeper, the shell being in that respect more like 
the variety obesa, which it also resembles in the 
sloping underside ; the aperture is proportionately 
larger than in that variety. The spiral lines on 




there are also important differences in the arma- 
ture, the lower horizontal parietal fold being very 
short, not extending on either side beyond the two 
lower arms of the main fold (see fig. 87^, which 
shows part of the parietal wall with its folds). Of 
the palatal armature, the first, second, and third 
folds are more elevated ; the first is bilobed, and 
above the posterior portion of the second occurs a 
very short additional fold. The vertical plate is 
also more elevated, and in place of the usual 
denticle posteriorly to its lower extremity is 
found an elevated ridge quite united to the 
plate. Fig. Sja shows the anterior and fig. 
876 the posterior aspect of both armatures. The 
specimen figured is in the collection of Mr. 
Ponsonby. 

{To be continued.) 



Fig. 86.— Plectopylis achatina var. casta'nea. 

the last two and a-half whorls are visible without 
the aid of a lens. The specimen figured was 
received by me from Miss Linter. 

Plectopylis achatina var. byeviplica (*) (figs. Sja-c) 
has a much shallower umbilicus, and is thinner 
and more fragile than any other form of P. achatina 
known to me. It is somewhat like the variety 
infrafasciata, but it is devoid of the white band on 
the lower side ; the last whorl also widens a little 
more than in that variety, but is less deflected, and 
the aperture is more sloping from top to base ; 






b c 

Fig. 87. — Plectopylis achatina var. breviphca. 

(*) Plectopylis achatina var. breviphca, n. var. (figs. S'/a-c), 
differs from the type and all the other known varieties by the 
much more shallow umbilicus. It resembles the variety 
infrafasciata in outline, but it is of a uniform dark brown, 
with a somewhat polished surface, and the last whorl widens 
more suddenly at the aperture. The basal horizontal parietal 
fold is very short, not extending on either side beyond the 
two lower arms of the main median fold ; the first palatal 
horizontal fold is considerably more elevated than in the 
other forms, and is bilobed ; the second and third horizontal 
folds are also more elevated, the latter fold has a short fold 
above its posterior portion ; the vertical plate is also more 
elevated, and in place of the usual denticle posteriorly to its 
lower extremity is .m elevated ridge, quite united to the 
plate. — Mjijf^.r diameter, ig millimetres; minor diameter,. 
16 millin.etrcs; altitude, 7 millimetres.— Habitat, Burma.— 
Type in Mr. Ponsonby's collection. 



170 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LANDSHELLS 

AND NEW FORMS OF PLECTOPYLIS. 
By G. K. Gude, F.Z.S. 

{Coiiliinied from page 135.) 



pLECTOPYLIS Unterae (figs. 8Srt-f), from Pegu, 
was described by Dr. von Mollendorff in the 
" Nachrichtsblatt der Deutschen Malakozoologi- 
schen Gesellschaft," 1S97, p. 28. The shell is 
sinistral, solid, discoid, widely umbilicated, pale 
yellow, transversely streaked and flammulated 
with chestnut, finely and regularly ribbed, smoother 
below, decussated with microscopic spiral lines. 
The spire is slightly conical, the apex scarcely 
produced, and the suture linear. There are six 
whorls which increase slowly and regularly, and 
are a little flattened above and rounded below ; 
the last is slightly angulated above the periphery 




Fig. SS.—PkciopyUx liii/erae. 

and around the umbilicus, and descends rather 
abruptly and deeply in front. The aperture is 
oblique, heart-shaped. The peristome is white, 
thickened and strongly reflexed ; its margins are 
united by a strong flexuous raised ridge on the 
parietal callus. The parietal armature is composed 
of a slight median horizontal fold, which proceeds 
from the apertural ridge, is interrupted for a short 
distance and then continues parallel with the 
suture for about a quarter of the last whorl ; it then 
gives off a shortly descending, slightly reflexed 
arm, which is provided anteriorly at the lower 
extremity with a short horizontal ridge; the fold 
then rises obliquely for a short distance and finally 
bifurcates ; the lower arm of the hifiircation is the 
longer, and descends obliquely, its lower extremity 
being provided posteriorly with a short horizontal 
ridge ; the upper arm at first continues to ascend 
obliquely, then deflects horizontally close to the 
suture ; a short, free, thin, horizontal fold occurs 
below the two lower arms, not extending beyond 
on either side (see fig. 8gd, which .shows the parietal 
wall with its folds). The palatal armature consists 
of : first, a thin long horizontal fold near the 
suture and parallel with it ; secondly, a shorter 
but stronger broad horizontal fold, which deflects 
a Utile and is slightly indented posteriorly ; 
thirdly a still shorter, broad, straight horizontal 
fold ; fourtb.lj, a strong broad vertical plate, 
which intercalates between the two lower arms of 

November, 1898.— No. 54, Vol. V. ' 



the parietal fold ; this plate is inclined towards 
the aperture, and its edge is thickened and reflexed ; 
near its lower extremity on the posterior side 
occurs a strong little denticle, which is elongated 
horizontally ; fifthly, a short thin horizontal fold 
close to the lower suture, having an elongated den- 
ticle a little above its posterior extremity. The 
species is closely allied to Plectopylis achat ina, but 
the spire of the present shell is much more raised, 
the umbilicus is much deeper, and the whorls more 
rounded. In the armature this species further 
differs from P. achatina in the median parietal fold 
being interrupted and much slighter, the branched 
portion being relatively much more elevated ; the 
lower free horizontal parietal fold is very short, so 
that this part of the armature, while differing 
from the typical forms of P. achatina, recalls the 
condition which obtains in the var. brevipUca of 
that species. The specimen figured, which I 
received from Miss Linter, was labelled with 
the habitat, " Moulmain." It measures : major 
diameter, 16 millimetres ; minor diameter, 13 
millimetres ; altitude, 6 millimetres. 

Plectopylis linteiae var. fusca (i) (figs. Sga-f). Mr. 
Ponsonby possesses a shell labelled P. paehystoma 
var. minor, which I am unable to separate speci- 
fically from P. Unterae, but which differs from 








d e / 

Fig. 89. — Plccti'pylis Unterae, var. fusca. 

the typical form of that species in being of a 
unicolorous dark-brown, in the peristome being 
livid instead of white, and in the shell being 
thinner in texture. The armatures are identical 
in both forms. Fig. Sgd shows the parietal wall 
with its folds, while fig. 89^ gives the anterior, and 

(1) Plectopylis lintcrat: var. fusca, n. var. (figs. 8917-/), differs 
from the type in being unicolorous dark-brown, a little paler 
below, in being thinner in texture, and in tlie peristome 
being livid. Major diameter, i4'5 millimetres ; minor 
diameter, 12-5 millimetres ; altitude, 5'5 millimetres. — 
Habitat, Burma. =Type in Mr. Ponsonby's collection 



SCIENCE-GOSSIP. 



171 



89/" the posterior aspect of both armatures ; all 
three figures are enlarged. Figs. 8ga-c show the 
entire shell in three different views, all of natural 
size. 

Plectopylis caintsi (-) (figs, goa-g). I base this new 
species upon a single unnamed specimen received by 
me from Mr. Robert Cairns, to whom it was sent 




« / g 

Fig. 90. — Plectopylis cnirnsi. 

by a correspondent in Singapore. Nothing is known 
of its origin, but the shell, which is somewhat de- 
corticated, appears to have come in contact with 
red colouring matter, so that it is not improbable 
it was imported with dye material from Burma, 
which country, judging from the characters of the 
shell, may reasonably be supposed to be its native 
place. At first I was kiclined to refer the speci- 
men to Plectopylis acliamin, but its more rounded 
contour led me to su.spect that it was an un- 



(2) Plectopylis caintsi, n. sp. (figs. 9017-^), shell sinistrorse, 
discoid, solid, widely unibilicated, yellowish corneous, finely 
and regularly ribbed, and decussated with microscopic spiral 
lines. Spire depressed, apex scarcely prominent, suture 
distinctly impressed ; whorls five and a-half, tumid above, 
rounded below, increasing slowly and regularly, the last de- 
scending moderately in front ; aperture oblique, cordate, a 
little inflexed at the upper outer margin. Peristome white, 
strongly thickened and rcflexed; the inargins united by a 
strong raised flexuous ridge on the parietal callus, notched 
at the junctions above and below. Parietal wall with a 
strong median fold, given off from the apertural ridge, 
revolving round about a quarter of the last whorl, but inter- 
rupted at the middle ; near its posterior extremity occurs 
a branched fold in the form of the Greek letter A, i.e. an 
obliquely ascending fold, having anteriorly at its lower ex- 
tremity a slightly ascending ridge and posteriorly a short 
support ; it is deflexed horizontally at its upper extremity, 
and at about its middle it gives ofl an obliquely descending 
arm, which deflects horizontally at its lower extremity. 
Palatal folds, five : the first, thin, horizontal, near the suture, 
a little indented and reflexed opposite the upper extremity of 
the oblique parietal fold ; the second, horizontal, a little 
shorter and deflexed posteriorly, provided with a small den- 
ticle a little above its posterior extremity ; the third, still 
shorter, but broader, horizontal, crescent-shaped, its con- 
cave side towards the fourth, which is vertical, very strong, 
inclined towards the aperture; near its lower extremity on 
the posterior side occurs a minute denticle ; the fifth is 
horizontal, short and very thin. — Major diameter, i8'5 milli- 
metres; minor diameter, I5'5 millimetres; altitude, 6 milli- 
metres. — Habitat, probably liurma. — Typo in my collection. 



described form, and this suspicion was confirmed 
on my opening the shell, for I then found the 
armature to constitute a connecting link between 
that of the groups of P. achatina and P. ponsonhyi. 
I have much pleasure in dedicating this new species 
to Mr. Cairns, who was kind enough to allow the 
specimen to pass into my collection. P. caintsi is 
flatter and more rounded in outline than P. achatina ; 
the whorls are more rounded and not angulated, 
the last whorl widens less at the aperture, the 
suture is more impressed, the umbilicus less deep, 
and the peristome is white. The parietal armature 
differs from that of P. achatina and its allies in the 
median fold being interrupted in the middle and 
separated from the branched portion which is in 
the form of the Greek letter A, and in the total 
absence ot the horizontal fold near the lower 
suture (see fig. 90(1?, enlarged, which shows the 
parietal wall with its folds). In the palatal arma- 
ture there are also some minor differences : the 
first horizontal fold is indented opposite the upper 
arm of the branched parietal fold, a feature I have 
not observed in any other species ; the vertical 
plate is also much narrower than in P. achatina, 
leaving more space for the soft parts of the animal 
to emerge (see fig. 90^;, which shows both armatures 
from the anterior side, and fig. 90/, from the 
posterior side, both enlarged) ; and, finally, the 
denticle behind the fifth horizontal fold, present 
in every other known species of the group of 
P. achatina, is absent (see fig. 90^, enlarged, which 
shows the inside of the outer wall with the palatal 
armature in situ). 

Plectopylis (?) iamcahensis (figs.9i«,&), from Ceylon, 
was described and figured by Dr. F. Jousseaume 
in the " Memoires de la Societe Zoologique de 
France," vii. (1894), p. 27S, t. 4, f. 8. As I have 




a • h 

Fig. gi.— Plectopylis {?) lamcabensis (after Jousseauir.e). 

been unable to obtain a specimen of this species, I 
have been compelled to rely upon Dr. Jousseaume's 
description, and to copy his figures of the shell. It 
is described as follows : shell subperforate, trochi- 
form, stout, somewhat thin, striated and surrounded 
on the last whorl by three threadlike ridges, 
diaphanous, shining, corneous white, apex obtuse, 
suture impressed, crenulate; whorls seven and 
a-half, flattened, the last angulate, not descending; 
base more convex, radiately striate ; aperture 
scarcely oblique, subangulate, lunate ; peristome 
simple, straight, columellar margin sloping, near 
the umbilicus narrowly dilated. Diameter, 4 milli- 
metres ; altitude, 3 millimetres. Habitat, Nuwcira, 



172 



SCIENCE-GOSSIP. 



Eliya. No mention whatever is made of any 
armature, and the systematic position of the 





4- 




Fig. 92.— Kn/iVZ/rt (?) engcrdi (after Jousseaume). 

species, therefore, remains doubtful ; if it really 
be a Plectopylis it will in all probability be 



found to belong to the section Sykesia. "Mr. Sykes 
has doubtfully suggested (Proc. Malac. Soc. 
London, iii. (189S), p. 71) that it belongs to the 
genus Sitdlu ; but I do not think this is probable. 
In the same work (p. 277, t. 4, f. i) Dr. Jousseaume 
described another shell which he also places in 
Plectopylis, i.e. P. eugenii. In this case also no 
mention is made of armature ; moreover, the figure 
given, which I have copied for convenient reference 
(see fig. 92), does not at all give the idea of a 
Plectopylis, and I agree with Mr. Sykes in thinking 
that it may belong to the genus Kaliella. 

Note. — By an oversight fig. 78/ on page 74 has 
been placed upside down. 

{To be continued.) 



SCIENCE-GOSSIP. 



239 



ARMATURE OF HELICOID LANDSHELLS 

AND A NEW SPECIES OF PLECTOPYLIS. 

Bv G. K. GUDE, F.Z.S. 

{Continued from page 172.) 



'TpHREE specimens of an unnamed Plectopylis 
■*• were submitted to me by Messrs. Sovverby 
and Fulton, who state that they have unfortu- 
nately no record of the origin of the shells. Upon 
examination I found them to belong to an un- 
described form, and I have now pleasure in 
associating with this new species the name of Mr. 
G. B. Sovverby i}). The present shell is closely allied 
to Plectopylis plcctostoma and P. affinis, a fact which 






e f 

■Plectopylis sowerbyi. 

led me to re-examine my own specimens of these 
two species, and among a lot of P. plectostoma 
received from Miss Linter in 1891, labelled 
"Khasia Hills," I found a decorticated specimen 
which undoubtedly belongs to the new species. 

(1) Plectopylis sowerbyi, n. sp. (fig. 93^-/.). — Shell 
sinistral, widely umbilicated, discoid, dark corneous, 
regularly ribbed and radiately distantly plaited, 
strongly decussated above by spiral ribs, less 
distinctly so below. Whorls six, narrow, increas- 
ing slowly and regularly, somewhat flattened 
above and rounded below, the last not descend- 
ing in front. Six or seven spiral ridges, probably, 
when fresh, bearing rows of hairs, pass round 
the whole of the body-whorl, the first just above 
the slightly angular periphery, the others below 
it. Aperture ear-shaped ; peristome slightly 
tinted with rosy-pink, scarcely thickened, and a 
little reflexed ; the upper outer margin a little 
depressed; parietal callus slight, without raised 
I'idge at the aperture. Umbilicus deep and 
wide. The parietal armature consists of a 
strong vertical plate, provided at its lower ex- 
tremity with a short support anteriorly, and a 
small denticle posteriorly. The palatal arma- 
ture is composed of six more or less horizontal 
folds, the first very slight and short, near the 
suture, the four next longer and more elevated, a 
little deflexed posteriorly, the sixth slight and very 
short. — Major diameter, 7-9 millimetres; minor 
diameter, 6-25-7-5 millimetres; altitude, 3'75-475 
millimetres. — Habitat, Khasia Hills, Assam. — Type 
in my collection. 

January, 1899. — No. 56, Vol. V. 



P. sowerbyi can at once be distinguished from 
P. plectostoma by the following characters : it is 
flatter, being less raised in the spire ; the umbilicus 
is more open ; there are only six whorls, the last 
not descending in front ; the peristome is scarcely 
thickened and not much reflexed, and there is no 
raised ridge on the parietal callus. In the arma- 
ture there are also important differences : the 
vertical parietal plate in P. plectostoma gives off from 
its upper extremity anteriorly a horizontal fold, 
which is absent in P. sowerbyi, where the plate in 
question is only provided with a support anteriorly 
and a denticle posteriorly below, and there is no 
horizontal fold below it ; so that in this respect 
the present species differs from both its allies (see 
fig. 93/, which shows part of the parietal wall with 
its armature). The palatal armature is in one 
series, and consists of six horizontal folds. The 
first fold is very short and slight ; the second 
longest ; the third, fourth, and fifth each a little 
shorter than its predecessor ; the sixth slight and very 
short (see fig. 93^, which shows the inside of the outer 
wall with its folds). All the figures are enlarged. 

In addition to the specimen from the Khasia 
Hills, mentioned above, I possess an immature 
shell of unknown origin, which I also refer to 
P. sowerbyi. The last whorl of this specimen is 
nearly complete, but the armature, which is 
identical with that of the mature shells, is situate 
at half a whorl from the aperture. 

Plectopylis alphonsi (fig. 94), from the Province 




Fig. 94. — Plectopylis alphonsi. 

of Monpin, Eastern Thibet, was described by 
Mr. G. P. Deshayes in the " Nouvelles Archives 
du Museum d'Historie Naturelle de Paris," vi. 
(1870), p. 22, and figured in the same work, ix. 
(1S73), t. 2, figs. 22-24. The species has not 
hitherto been referred to the genus Plectopylis, but 
the palatal armature clearly indicates its generic 
position. Mr. Pilsbry (" Manual of Conchology," 
ix. p. 211) has placed the species in the genus 
Eulota, but this is doubtless owing to the fact that 
Mr. Deshayes makes no mention of armature in 
his diagnosis. Some time ago Mr. Gredler sent 



240 



SCIENCE-GOSSIP. 



me for inspection a single immature specimen from 
Kouei-Tchou, which he doubtfully referred to the 
present species. Mr. Mabille, who was kind enough 
to compare the shell for me with the type of P. 
alphonsi in the Paris Museum, has confirmed its 
identity with P. alphonsi, and subsequently the 
writer had an opportunity of inspecting the type 
specimen. Unfortunately there was only one 
specimen in the museum, so that I was unable 
to examine the details of the armature. Five 
horizontal palatal folds are visible through the 
shell-wall, but probably there are six folds, the first 
near the suture being seldom visible from without. 
In general form, as well as in the palatal armature, 
P. alphonsi appears to be allied to P. stenochila. 
The present species was described by Mr. 
Deshayes as follows : 

" Shell depressed, orbiculate-discoid, thin, fragile, 
corneous-brown, yellowish-white, obliquely lineate 
and irregularly punctate ; spire depressed, scarcely 
convex ; whorls seven, narrow, sub-equal, finely 
plicate and concentrically sub-striate above ; the 
last angulate above, convex below, polished, widely 
umbilicated ; the perspective umbilicus a little 
deflected at the aperture ; aperture semi-lunate, 
oblique, slightly compressed ; peristome sinuous, 
reflected ; columellar margin wide, with a denti- 
form thickening. — Major diameter, g millimetres ; 
minor diameter, 8 millimetres ; altitude, 35 
millimetres." 

Mr. Gredler's specimen, shown in fig g^a-c, has 
the peristome just formed, but is not quite mature. 
It does not possess any armature, but only shows 
a few denticles in that part of the shell where the 
palatal folds would be expected to occur ; it has 
besides some traces of denticles at a spot where a 
former set of immature barriers might be expected 
to have existed. This is the first case of a Pkctopylis 
without any armature which has come under my 
observation. 

Pkctopylis hanleyi was described by Lieut. -Col. 
Godwin-Austen, in the " Annals and Magazine of 
Natural History" (5) iv. (1879), p. 164. No 
figure has been published, and only one specimen 
is known. This is in the collection of Mr. 
Sylvanus Hanley, but I have been unable to 
inspect it, and I am therefore only able to 
copy the original description. The same remark, 
unfortunately, applies to the next two species. 

The description of Pkctopylis hankyi runs thus : 

" Shell sinistral,. depressedly conoid, openly umbili- 
cated, probably hirsute when young. Sculpture 
coarse, irregular, transverse ridges. Colour uni- 
form ochraceous. Spire conoidal ; apex blunt, 
smooth. Suture well marked. Whorls six, close- 
wound, convex ; aperture semicircular, diagonal ; 
peristome somewhat thickened, white, with a thin 
callus on the parietal margin [wall (?)] not to the 
extent of a ridge. Size. — Major diameter, 55 ; 
minor diameter, 5 ; altitude, 3 millimetres. 

" Parietal vertical lamina simple ; palatal plicae 
in two rows, four long in front, four short behind, 
and one basal long- 



"This shell is very distinct; it has somewhat 
the form oi P. plectostoma, but is not so angular on 
the periphery, while the internal plication is quite 
different, besides being so very much smaller in 
size. Sikkim (?) ; no history. Only one specimen, 
in the collection of Mr. Sylvanus Hanley." 

Pkctopylis vallata was described by Mr. Heude, 
in the "Journal de Conchyliologie," xxxvii. (i88g), 
p. 45. I translate the description as follows : — 

" Helix vallata. Shell discoid, laciniate at the 
periphery; below furnished with acute distant plaits, 
interspersed with minute striae trellis-like ; lat. 10, 
alt. 5 millimetres. Tchen Keou. This Pkctopylis 
recalls P. stenochila, but its dimensions are nearly 
double. Apart from the presence of the peri- 
pherial fringe, it may be stated that the inferior 
plaits are more numerous, and that their inter- 
vening spaces are trellised. These characters 
separate it from its congener of the right 
bank." 

Plectopylis jugatoria was described by Mr. F. C. 
Ancey in the " Bulletin de la Societe Malacologique 
de France," 1885, p. 127. The diagnosis may be 
thus translated : — 

" Shell widely and deeply umbilicated, depressed, 
scarcely convex above, apex very prominent, some- 
what solid, brownish-red, angulated, the upper 
oblique lines decussated with spiral ones (except at 
the apex), produced into laciniate cilia at the peri- 
phery ; below smoother, spiral lines finer. Whorls 
six, slowly increasing, separated by a linear suture, 
almost flattened, the first altogether flat, the last 
widened around the umbilicus, strongly descend- 
ing at the aperture, rather acutely angulated 
above, perspectively convex round the umbilicus 
below ; aperture strongly oblique, not wide ; semi- 
lunate ; basal margin regularly rounded, scarcely 
angled at the periphery ; peristome thickened and 
reflexed all round, but chiefly at the base, whitish; 
the margins connected by an appressed plate, on 
both sides at the junctions slightly channelled 
similar to Helix achatina Gray. Palate provided 
below with five parallel plates with another strong 
nail-shaped plate opposite the parietal margin; 
if others exist I have not been able to examine 
them. 

"Major diameter, 125-1325; minor diameter, 
11-5-12; altitude, 55; width of aperture, 4-5 milli- 
metres. Province of Kouei-Tchou. 

" The shell which I have before me is a near 
relative of Helix fimbriosa'Ni&xiens, of the Provinces 
Hoo-Nan and Kiang-Si. It can easily be dis- 
tinguished from that species by the last whorl 
strongly descending at its extremity, its still more 
oblique aperture, the fine concentric striae of the 
lower surface, which is also marked with stronger 
lines of growth, and especially by the two margins 
of the aperture being united by a calcareous plate 
similar to that of the Indian Plectopylis, such as 
P. achatina, kiophis, cyclaspis, brachypkcta, etc. At 
the junction of the two margins exists a little 
channelled fold as in those species. I believe 
these internal plates are much like those in P. 
fimbriosa ; but the small number of specimens which 
I had at my disposal did not allow me to sacrifice 
one to examine the fact completely." 

Subsequently Mr. Ancey appears to have modi- 
fied his view as to the nearest allies of P. jugatoria, 
for he informs me in a letter that this species is 
allied to P. laminifera. 

(To be continued.) 



332 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOID LAND SHELLS 

AND NEW FORMS OF PLECTOPYLIS. 

By G. K. Gude, F.Z.S. 

( CmtinueA from page 240. ) 



Plectopylis giardi (figs. 95a-c.), from Cao-Bang, 
Tonkin, was described and figured by Dr. H. Fischer 
in the " Bulletin Scientifique de la France et de la 
Belgique," xxviii. (1898), p. 320, t. 17, ff. 17-21. 
The shell is dextrous, very deeply and rather 
widely umbilicated, brown, finely striated, and 
decussated with microscopic spiral lines above. 
The spire is depressed, conical, the apex prominent 
and the sutvire distinctly impressed. There are 
eight whorls, which increase slowly and regularly 
and are somewhat flattened above and tumid 
below ; the last rounded, obsoletely angulated 

b 




Fig. 95, Plectopylis giardi. 



above the periphery, descends shortly and sud- 
denly in front. The aperture is oblique, sub- 
circular; the peristome white, rounded, much 
thickened and strongly reflexed, its margins being 
united on the parietal callus by a strongly 
thickened and raised flexvious ridge, which is 
slightly notched at the junctions above and below. 
Near the apertural ridge occurs a short but strong 
oblique fold. (See figs. 95a and c.) The pai-ietal 
armature consists of two strong obliquely diver- 
gent vertical plates, the anterior one shorter, 
with a slight support on each side at the lower 
extremity ; a short, thin, horizontal fold occurs 
immediately above it; the posterior one longer, 
somewhat attenuated at the lower extremity but 



rather truncated above. (See fig. 95e, which 
shows part of the parietal wall with its armature). 
The palatal armatvire consists of six short folds : 
the first thin, horizontal, near the suture ; the 
next four stronger, semicircvilar, more or less 
oblique, and intercalated between the two ver- 
tical parietal plates ; the sixth long and thin. 
The second of these folds is nearly straight, a 
little attenu.ated at both extremities, while the 
third, fourth, and fifth are almost vertical, 
reflexed anteriorly above and posteriorly below. 
Plectopylis giardi and the next species are allied 
to P. schlumbergeri figured in this series of papers 
(vol. iv., 1897, p. 138, f. 58), P. jovia (ihid., f. 59), 
and P. villedaryi (ibid., p. 139, f. 60), but can be 
distinguished at once by the double vertical 
parietal plate. I am much indebted to Dr. H. 
Fischer, who kindly allowed me to make use of 
the photographs of the type shells, which are 
copied in figs. 95a-d. Figs. 95e and / (enlarged) 
are from a specimen, one of three collected by 
Dr. Billet, obligingly furnished by Prof. Giard, 
and now in my collection. This specimen measures : 
major diameter, 20 millimetres ; minor diameter, 
17-5 millimetres ; altitude, 12 millimetres. 

Plectopylis congesta( ' ), figs. 96a-/. A shell received 
from Messrs. Sowerby and Fulton as P. giardi 
proved upon examination to differ from that 
species as well as from all other known forms of 

(^) Plectopylis covigiesfa, n. sp. (fig.96a-/). — Shell 
dextrous, deeply and very widely umbilicated, 
dark corneous brown, somewhat paler below, finely 
striated and decussated with microscopic spiral 
lines which become obsolete below the perij)hery. 
Spire depressed, conical ; apex prominent ; suture 
slightly impressed. Whorls eight, rounded, in- 
creasing slowly and regularly, the last distantly 
ribbed, suddenly descending somewhat deeply 
in front; aperture oblique, subcircular. Peri- 
stome pale fuscous, thickened and reflexed; the 
margins united on the parietal callus by a strongly 
raised flexuous ridge, slightly notched at the 
junctions above and below. Parietal wall with a 
strong horizontal entering median fold, running 
parallel with the suture and united to the apertural 
ridge. Parietal armature consisting of a strong 
vertical plate, furnished above and below an- 
teriorly with a slight ridge or support; viewed 
laterally this plate is seen to be slightly notched 
at the upper extremity; a second shorter and 
thinner vertical plate, the lower half of which is 
obliquely deflexed, occurs behind the first; the 
lower extremities of the two plates are united by 
a slight horizontal ridge. Palatal folds six ; the 
first slight, horizontal ; the second, third, fourth, 
and fifth semicircular, oblique > the sixth, hori- 
zontal. — Major diameter, 16-18-5 millimetres; 
minor diameter, 14-15 millimetres ; altitude, 9-10 
mm. — Habitat, Tonidn. — Type in my collection. 



SCIENCE-GOSSIP. 



333 



Plectopylis. Its exact locality, unfortimately, was 
not stated. It differs from P. giardi in being 
smaller, in having a \vider umbilicus, in the 
whorls being less tumid and, as a consequence, 
the two sets of barriers are in close proximity to 
each other, so that less space is left for the body 
of the animal when extended out of the shell. 
The horizontal fold at the aperture is longer than 
that of P. giardi, and instead of being oblique, as 
in that species, it is parallel with the sutiu-e and 
is, besides, distinctly united to the apertural 
ridge. The principal difference, however, lies in 
the armatiire, the anterior parietal plate in P. 
congesta being longer than the posterior one. 









fig. 96, Plectopylis congesta. 

whereas the reverse condition obtains in P. giardi. 
Moreover, the horizontal fold above the anterior 
vertical plate of that species is absent in the 
present shell, while in its place occurs a horizontal 
ridge uniting the bases of the two vertical plates. 
The third, fourth, and fifth palatal folds are 
oblique instead of being almost vertical, as in 
P. giardi, and nearly straight instead of having 
their upper and lower extremities bent forwards 
and backwards respectively. The specimen shown 
in figs. 96a-c is in Mr. Ponsonby's collection. It 
measures 18-5 : 15 : 10 millimetres, while figs. 9Gd-f 
(magnified) are taken from my shell, the dimen- 
sions of which are 16 : 14 : 9 millimetres. 

(2) Pledopylis achaUnavsiY.repercussoides,n.Ya,r. 
— This differs from the type in being angulated 
above at the periphery, also below roimd the 
umbilicus, and in the peristome being white. 
Armature same as In the type.— Major diameter, 
25-27 millimetres ; minor diameter, 19-5-22 milli- 
meters; altitude, 8-5-9-5 millimetres. — Habitat 
Biirraa. — Type, ir ray collection. 



The two foregoing species are connected by an 
intermediate form of Pledopylis still undescribed, 
but shortly to be pviblished by Dr. Fischer, and 
which, owing to the kindness of Professor Giard, 
I was enabled to inspect. This interesting shell 
combines the characters of the parietal barriers of 
both the above species, having the two divergent 
vertical plates and the upper horizontal fold of 
P. giardi, as well as the lower horizontal fold of 
P. congetta. In its palatal armatui'e it differs 
somewhat from both. 

Pledopylis achatina var. repercussoides (^). In 
addition to the new forms described in my pre- 
vious communications (ante pp. 115-133, et seq.), I 
possess a specimen which is intermediate between 
typical P. achatina and P. repercussa, having the 
contour and the white peristome of the latter, but 
the armature of the former. Thinking it vmdesirable 
to base a variety on a solitary shell, it was tem- 
porarily placed on one side. Since then Mr. W. E. 
Collinge has kindly sent me some shells of Pledo- 
pylis for examination belonging to the museum of 
Mason's College, Birmingham. Among these I 
found tlu'ee specimens which are identical with 
my shell ; all doubts as to its merits to rank as a 
variety are therefore removed. The variety reper- 
cussoides differs from the typical P. achatina in 
being angailated above at the periphery, and 
below rovmd the lunbilicus, resembling in this 
respect P. repercussa, with which it has also the 
white peristome in common. The armature is 
identical with that of the type. In colour the 
shell is chestniit brown above, while the vimbilical 
region is white, a feature it shares with the 
variety infrafasciata. 

(To he continued.) 



SCIENCE-GOSSIP 



15 



ARMATURE OF HELICOID LAXDSHELLS 

AND NKW SPECIKS OF PLECTOI'VLIS. 
By G. K. (;ii>E, F.Z.S. 

(Continui-d fioiti I'ol. I'., /xtcf JJJ.J 



PlectopyHx aiislcni (') (figs, gja-f.j. F'our speci- 
mens, three adult, one yoiuii^, of an unnamed form of 
Plectopylis, difterini^ from all described species, have 
been kindly placed in m\' Inands for examination by 
Lieut. -Col. Godwin- Austen, with whose name I have 
much pleasure in associating this new species. The 
new shell is allied to PUclopylis oglci (figured in 
SciENCE-Gossii', N.y. iv. (1898) p. 263, fig. 68), but 
it can readily Ije distinguished from that species by its 
concave spire ; it is also much smaller and much 
more flattened. In its parietal armature, it differs in 
having a short and a long median horizontal 
fold and a denticle in front of the vertical 
plate, all of which structures are absent in Plectopylis 
oglei. A comparison of the figures will also indicate 
differences in the palatal armatures of the two species. 
Plectopylis aiisfeiii has further some affinity, as re- 
gards palatal armature, with /'. niiispratti (c.f. 









O} 



Fig-. 97. — Plectopylis aiistfiii. 

SciEN'CE-Gossii', N.S. iv., 1897, p. 10, f. 45), 
but the latter is a dextral species and the parietal 
armature is tjuite different, as also in the general shape 
nf the shell. The immature specimen of /'. aiisteni 
referred to above has completed five-and-a-half 
w lie iris, and is interesting from possessing two sets of 
armature a quarter of a whorl distant from each other ; 
these differ considerably from the mature barriers ; 
the parietal armature here consists onh' of the vertical 
plate and a very short, slight, horizontal fold in front 
of it. The palatal armature is similar to that of 

(1) Plectopylis aiistciii, n.sp. (figs, qja-f). — Shell 
sinistral, discoid, widely umljilicated, ochreous cor- 
neous, covered with a deciduous velvety cuticle ; 
finelv and closely ril)bed, decussated by raised spiral 
lines, rather distant on the upper side. One of these 
spiral lines forms a ridge or keel on the upper angle 
of the whorls above the periphery, revolving above 
Jin:-;. 1859. — No. ()i. \'oI. \'l. 



mature shells, except tiuu the folds, ridge and 
denticles are very small and slight. Lieut. -Col. 
Godwin- Austen informs me that the shells were 
collected by his assistant, Mr. INL T. Ogle, in the Diyung 
\ alley, Singpho, Assam. 

Plectopylis ivoodthorpei (-) (figs. 98 a-Ji). Three 
specimens — two mature, one young — another unde- 
scribed form of Plectopylis, have also Ijeen most 
obligingly sent to me for examination by Lieut. - 
Colonel Godwin-Austen, who informed me that they 
were collected in 1894 b_\- the late Colonel Wood- 
thorpe, R.E., after whom they are now named. This 
new species is a very interesting one forming as it 
does a connecting link between the group of Plecto- 
pylis poiisonbyi and that of /'. plectostoiiia ; on the one 
hand it resembles /'. poiisonbyi in the posterior 
portion of the palatal armature (see fig. 98/"). and 
/'. leiicochihi in iis parietal armature (see fig. 98 t') ; 
it differs, however, from the other members of this 
group in having a series of horizontal folds anteriorh 
to the vertical palatal plate. On the other hand, 
this biseriatecharacter of the last-mentioned structure, 
unites it it with the group of /'. plectostoiiia. In out- 
ward appearance the shell of /'. woodthoipei nuich 

the suture as far as the third whorl. .Spire concave, 
apex a little raised, suture strongl)' impressed. Whorls 
6^, flattened above, roiinded below, obsoletel}- angu- 
laled around the umbilicus ; increasing slow I_\- at first, 
the last widening rather suddenly, and descending half 
the width of the whorl in front ; aperture oblique, 
cordate. Terislome white, strongly thickened and 
reflexed, the margins united b)- a strong laised flcxuou.s 
concave ridge, slightl)' notched at the junctions above 
and below. Umbilicus wide and rather shallow. 
Parietal armature consisting of a short median hori- 
zontal fold close to the apertural ridge, and a second 
longer one farther back, rather elevated posteriorly, 
gradually descending on the shell wall anteriorly ; 
below its posterior extremity occurs a small denticle ; 
still farther back is found a strong vertical crescent- 
shaped plate, the upper and low er extremiiies of which 
are deflected posteriorly. Palatal armature composed 
of six short horizontal folds, the first longest, near the 
suture, provided at its posterior extremit)- with an 
elongated denticle ; the second, third, fourth, and 
fifth a little oljliquely depressed posteriorly where the_\- 
are united by a slight vertical ridge, which is con- 
tinued above the second and below the fifth folds ; 
on the posterior side occur five elongated denticles, 
the four lower of which correspond to the four folds, 
w hile the fifth is situate near the upper extremity of 
the \ertical ridge ; the sixth fold is near the lower 
suture, and has also an elongated denticle posteriorly. 
— Major diameter, I7"5-I9 millimetres; minor dia- 
meter, i475-i6'5 millimetres; altitude, 5-6 milli- 
metres. — Plabitat, Diyung \'alley, .Singpho, Assam. — 
Type in the Natural Histoiy Museum, Sou.th Ken- 
sington. 



i6 



SCIENCE-GOSSIP. 



resembles P. shiroieusis {c.f. Science-Gossip, N.S. 
iii., 1896, p. 155, f. 20), but the former is much 
larger. The immature specimen referred to, wliicli 
has nearly six whorls formed, has the armature in- 
complete, and is instructive as possibly throwing 
some light upon the evolution of these structuies. 
The parietal armature here possesses the two vertical 
plates, but the horizontal folds given oft by the 
anterior plate are very short, being only one (juaiter 
of the length of those in the mature shells ; the thin 
fold near the lower suture is not compressed into a 
lamellar fold below the vertical plates, as is the case 
in the full-grown shells, and it rises much farther 
back (see fig. 98 g., which shows portion of the 
parietal wall with its armature . Of the palatal 
armature, only the posterior series ot pro- 





~^ 



0^ 




Fig-. 98. — Plcctopyiis 7voodthorpei. 

cesses is present, the anterior series having 
still to be formed : a fact clearly pointing 
to the more recent origin of the biseriate forms. 
The vertical plate is distinctly divided into two sub- 
equal portions, in consequence of the indentation in 
the middle being carried down to the base ; the ridge 
connecting the upper extremity of the vertical plate 
with the short horizontal fold above it is absent, but 
in its stead occurs near the latter a little denticle ; 
while posteriorly to the upper half of the vertical 
plate is found a distinct denticle, corresponding to 
the slight swelling in the same place, mentioned in 
the diagnosis {see fig. 98/2, which shows the inside 
of the palatal wall with its armature). 



Plectopylis {Sykesia) biciliala (figs. 99 a-e) from 
Ceylon was described by Dr. Pfeifter in the " Pro- 
ceedings of the Zoological Society,"' 1855, p. 112, as 
Heli.y biciliatii, and the shell is figured in " Ilanley 
and Theobald's Conchologia Indica '' (1875), t. 159, 
figs. I and 4. The systematic position of this shell 
remained uncertain for a long time ; it was placed in 
iV(7///;/« by Dr. Pfeifter (" Malak. Blatter" ii., 1855, 
p. 121), and in Discus., by Mr. H. Nevill (" Enum. 
Helic. Ceylan."" 1871, p. i), while finally Mr. S. 
Clesiin grouped it v\ith Macrochlainys (" Nomencl. 
Helic. viv." 1881, p. 45). It is unfortunate that 
Dr. Pfeiffer's types of this species cannot be found. 
They were described as from the late Major Skinner's 
collection, but Miss Linter who purchased the entire 
collection, kindly informs me that the shells in 
(juestion are not in it, and she does not think that 
Major Skinner ever possessed them there being no 
record of them in his catalogues. Mr. Edgar Smith 

(-) Pleclopylis zvoodthorpei, n. sp. (figs. 98 a-h). — 
Shell dextral, discoid, widely and deeply umbilicated, 
dark corneous, finely and regularly ribbed, closely 
decussated by microscopic spiral lines. Spire conical, 
apex prominent, suture impressed. Whorls 6A, in- 
creasing slowly and regularl}', flattened above, tumid 
bel<nv, the last scarcely wider than the penultimate, 
bluntly keeled above the periphery, widening a little 
towards the aperture, descending deeply in front. 
Aperture oblique, cordate ; peristome whitish, 
strongly thickened and reflexed, the margins united 
bv a strongly raised flexuous ridge, which is concave 
in the middle, and notched at the junctions above and 
l)elow. Parietal armature consisting of two nearly 
parallel vertical plates, the posterior one longer, 
slightly reflexed posteriorly at its lower extremity, 
and provided posteriorly at the upper extremity with 
a slight ridge ; the anterior one shorter, giving oft a 
horizontal fold anteriorly at each extremity, the 
lower less than half the length of the upper, ascend- 
ing obliquely : the upper revolving almost parallel with 
the suture, toUowing the deflexion of the whorl, and 
joining the ridge at the aperture. Below the posterior 
vertical plate rises a free, thin, horizontal fold, at 
first considerably elevated above the shell-wall, but 
suddenly becoming attenuated and threadlike, run- 
ning parallel with the lower suture, as far as the 
aperture where it is joined to the ridge on the parietal 
callus. Palatal armature in two series, the posterior 
series consisting of : first, a long thin horizontal 
iold near the suture ; secondly, a very long hori- 
zontal fold, extending anteriorly beyond the 
folds of the second series, with an elevated 
compressed denticle posteriorly ; thirdly, a very 
shor horizontal fold, deflexed posteriorly ; 
fourthly, a strong vertical plate, with an in- 
dentation at the middle, giving oft" posteriorly at its 
lower extremity an obliquely descending ridge, and 
provided at the same place with a small dentrcle ; at 
the base of the upper lobe of the vertical plate ox\ the 
posterior side occurs a slight swelling, while on the 
same side from its upper extremity runs a short ridge, 
connecting this plate with the thrrd horizontal fold ; 
fifthly, a long thin horizontal fold near the lower 
suture. The anterior series consists of three thin 
horizontal folds, the first longest the third shortest, 
all three descending a little anteriorly. — Major dia- 
meter, S75-10 millimetres, minor diameter, 7^25-8 
millimetres, altitude 3"25-4 millimetres. — Habitat, 
Fort Stedman. Burma. — Type in the British Museum. 



SCIENCE- GOSSIP. 



17 



has obligingly searched the British Museum collection 
for these types, hut without success. The species 
appears to be rare, for since it was first de- 
scribed, it has remained unobserved until Mr. H. 
B. I'reston found a single specimen at Patapolla, 
Ce\lon, as recorded by Mr. E. R. Sykes 
(" Proc. Malac. Soc, London," iii., 1898, p. 66), 
and Mr. O. Collett subsecjuently found two 

a b 




Fig. 99. — Pleciopytis lucUiata. 

specimens at Haputale (Sykes, op. cit. p. 160). 
The three specimens referred to agree with the 
figures in "Conchologia Indica," audit may, therefore, 
be safely assumed that they are correctly identified, 
and to Mr. Sykes belongs tlie credit of first pointing 
<nit the true systematic position of the species. The 
shell is convexly conical, narrowly umbilicated, 
dark corneous, translucent, finely and regularly 
ribbed, with a double keel at the periphery and a 



third a little above it, the lowest and uppermost 
l)eing provided with a fringe of coarse, curved, 
deciduous hairs. There are six convex whorls, which 
increase slowly and regularly, the base a little 
shining, tumid around the narrow umbilicus and 
concave towards the periphery. The aperture is sub- 
(juadrate, elongated, the peristome simple, acute. 
The parietal armature consists of two sin^ple obliquely 
ascending folds, separated by a distance of half a 
whorl, having the upper extremities somewhat 
attenuated and the lower truncate. (See fig. gg^f', 
which shows the parietal wall with its two folds). The 
palatal armature is composed of: first, a short, hori- 
zontal fold below the periphery, a little farther Ijack 
l)ut in a line with it a strong lamelliform denticle, 
ascending obliquely ; secondly, three denudes in a 
line horizontally and about equidistant, the posteiior 
one strongest ; thirdly, a short slight horizontal fold 
near the lower suture, rising near the aperture and re- 
volving as far as the second denticle. (See fig. 99t', 
which shows the inside of the outer wall with the 
palatal armature). The specimen shown in figs f^()a-c 
measures 6 millimetres in diameter, altitude 3 "5 milli- 
metres ; it is one of the shells collected by Mr. Collett 
and is in Mr. Ponsonby"s collection ; the armatures are 
figured from the specimen collected by Mr. Preston 
which is in Mr. Sykes' collection. 

'{To l>e continucii.) 



SCIENCE-GOSSIP. 



7S 



ARMATURE OF HELICOID LANDSHELLS 

AND NEW SPECIES OF PLECTOPVLIS. 

By G. K. GUDE, F.Z.S. 

(Continued froju page hy.) 



Pkdopylis {Sykesia) caliginosa (figs. \Ooa-e) from 
Ambagamuwa, Ceylon, was described and figured b_\- 
Mr. Sykes, in the ' ' Proceedings of the Malacological 
Society of London," iii. (1898), p. 72, t. 5, ff. 21, 22. 
The shell is lenticular, narrowly umbilicated, ochreous 
corneous, opaque, very finely and regularly ribbed, 
the ribs being rather more prominent above than 
below ; it is acutely keeled at the periphery, with a 
raised spiral line above the keel, quite close to it, as 
far as the apical whorl. The spire is conical, the apex 
obtuse, the suture impressed. There are five very 
slowly increasing whorls, flattened above, tumid 
below, the last scarcely wider than the penultimate, 
not descending in front. The aperture is almost 
vertical, lunate, and the peristome simple, acute. The 
parietal armature consists of two simple, sub-vertical 
plates which are somewhat thickened and truncate at 
the lower, and attenuated at the upper extremities ; 
these plates are separated by a distance of a quarter 
of a whorl, and the posterior one is the stronger (see 

a b c 






d 



07 



Fig-. 100.— Pleetopylis caliginosa. 

fig. ioO(f, which shows the parietal wall with its two 
plates). The palatal armature is in two vertica 
series : the anterior series consists of an obliquely as- 
cending short quadrate tooth near the peripherj-, and 
below this an obliquely descending lamelliform tooth, 
with a slight, horizontally elongated denticle below 
its posterior extremity ; the posterior series is similar 
to the anterior one, but the teeth are stronger and 
thicker in the former, while there is in addition a 
horizontally elongated denticle on the anterior side of 
the upper tooth. The specimen shown in figs. 
looa-c measures 6 millimetres in diameter, alt. 3 
millimetres, and is in the collection of Mr. Ponsonby. 
The armatures are figured from the type specimen in 
the collection of Mr. Sykes, who kindly permitted me 
to open the shell for the examination of the armature. 
Pleetopylis [Sykesia] clathraittla, \-ar. compressa, 
(figs, \o\a-c) was described and figured by Mr. 
Sykes in the "Proceedings of the Malacological 

t., 5, ff. 13, 14- It 



Society," iii. (189S), p. 72, 
Ai'G. 1899. — No. 6;, Vol. \'I. 



differs from the tvpe in being more elevated, in the 
more convex spire and the narrower umbilicus, while 
the raised ribs are scarcely visible. The armature is 




Figf. lor. — Pleetopylis clathratula var compressa. 

similar to that of the type. The specimen figured is 
in ]Nh". Ponsonby's collection ; it measures 5 milli- 
metres in diameter, altitude 2 '5 millimetres. 

Pleetopylis franqoisi (figs. i02(7-t') from Dco-ma- 
Phuc, Tonkin, was described and figured by Dr. II. 
Fischer, in the "Journal de Conchyliologie, xlvi. 
(1898), pp. 214-218, ff. I, 3, 4 (part published March, 
1899). The shell is dextral, deeply and widely um- 
bilicated, corneous, striated, and decussated with 
microscopic spiral lines above, which become obsolete 
at the periphery, the lower surface smooth and a 
little shining. The spire is depressed, conical, the 
apex prominent and the suture distinctly impressed. 
There are 7^ whorls, which increase slowly and regu- 
larly, and are somewhat flattened above and tumid 
below. The last whorl is at first obsoletely keeled 
above the periphery and angulated at the umbilical 
region near the parietal callus ; it descends shorth- 
and suddenly in front. The aperture is a little 
oblique, subcircular ; the peristome white, a little 
thickened and reflexed, its margins united l>y a 
parietal callus. The parietal armature is composed of 
two strong, obliquely divergent, transverse plates, the 
anterior one shorter, rounded at the upper and giving 
off an anterior ridge at the lower extremity ; a short 
thin horizontal fold occurs immediately above it ; the 
posterior plate longer, truncate at the upper, attenuated 
at the lower extremity. A free thin horizontal fold 
occurs below these plates, terminating on the one side 
just below the anterior plate, and on the other just 
in front of the posterior plate. (See fig. \02d, which 
shows part of the parietal wall with its armature). 
The palatal armature consists of six folds ; the first, 
rather short, thin, horizontal, near the suture ; the 
second longest of all, horizontal, deflected at the 
posterior extremity and becoming slowly attenuated 
anteriorly ; the third, fourth, and fifth stronger, semi- 
circular, oblique, their anterior extremities a little 
reflexed, their posterior ones a little deflexed ; the 
sixth thin, long, horizontal ; the second, third, fourth, 
and fifth give oft", about the middle, from the lower 
side, a slight callous ridge which connects them inter 
se ; between the posterior eiitremities of the fi!th and 



D 4 



76 



SCIENCE-GOSSIP. 



sixth folds is a horizontally elongated denticle. (See 
fig. I02tf, which shows the inside of the outer wall 
with the palatal folds, and fig. I02c, which gives the 
anterior view of both armatures). Plectopylis fraiiroisi 
is intermediate as regards its armature lietween /'. 
giardi and P. congesta, as already briefly stated when 
describing the latter species (Science-Gossip N.S. 
^"•' P- 333) ■ P- f>'ani;oisi differs from P. giardi, 1° in 
the anterior parietal plate being more oblique, and 
2° in this plate being rounded at the upper extremity 
instead of truncated ; 3° in having an addi- 
tional free horizontal parietal fold ; 4° in the second 
and sixth palatal folds being longer; 5° in the second, 
third, fourth, and fifth palatal folds being more oblique, 
and 6° in having in addition a denticle between the 
fifth and sixth folds ; 7' in the armature being further 
from the aperture, S° in the aperture being less oblique. 





Fig. 102. — Plectopylis frani:oisi. 

•and 9° in the peristome being considerably less 
thickened and reflexed. The shell is, moreover, 
considerably smaller, and the sculpture much stronger. 
From P. congesta it differs similarly in the charac- 
ters enumerated under Nos. 3, 4, 6, 8, and 9 ; while 
in the character of the anterior parietal plate it is 
still further removed, this structure in P. congesta is 
almost vertical, and it wants the upper free horizontal 
parietal fold, while the lower horizontal fold is 
joined to the two transverse plates. The unique 
specimen is in the collection of Professor Giard, 
who obligingly sent it to me for examination ; it is, 
unfortunately, slightly damaged, that portion of the 
parietal callus which bears the short fold near the 
aperture in the other species, together with the ridge. 



being broken off, so that it is impossible to say 
whether the present species differs from its two 
congeners in this respect. The shell measures major 
diameter 15.5 millimetres, minor diameter 13.5 milli- 
metres, altitude 8.75 millimetres. Figs, \02a-b are 
taken from photographs kindly furnished by Dr. H. 
Fischer. 

Plectopylis revoluta was described by Dr. Pfeiffer 
in the " Malakozoologische Blatter," xiv. (1867), 
p. 64, as from the Andaman Islands. Unfortunately, 
I have been unsuccessful in tracing the whereabouts 
of the specimens from which the diagnosis was drawn 
up, as Mr. Smith, who kindly searched the collection 
in the British Museum, has been unable to find them 
there ; and Professor Boettger informs me that they 
are not in the Pfeiffer collection acquired by 
Dr. Dohrn. This is all the more to be regretted as 
no Plectopylis has since been discovered in the 
Andaman Islands. The late Mr. Stoliczka (" Journ. 
Asiat. Soc. Bengal," xl. (1871), p. 223) wjis of 
opinion that this shell could hardly be distinct irom 
Plectopylis cyclaspis, his specimens of which agreed 
perfectly with the measurements given by Dr. Pfeift'er. 
He adds that amongst many thousands of shells from 
the Andaman Islands, he never received cyclaspis, and 
he doubted its occurrence there as much as that of 
/'.(7(7?(Z//;?rt, recorded by Tryon in " Proc. Asiat. Soc," 
1870, p. 88. It is advisable, I think, to consider 
P. revoluta synonymous with P. cyclaspis. 
Addenda. 
I'lectopylis giardi (fig. 103). — I append a figure 
showing the inside of the outer wall of F. giardi, with 




Fig-. lo^.^Phclopy lis giaidi (VaXataX folds). 

its palatal folds. This figure, by an oversight, was 
omitted when the species was described and figured 
(SciENCE-Gossir, N.S. v., p. 332, fig. 95). 

Plectopylis feddeiii (figs. 104^ and /;).— When con- 
sidering this species (Science-Gossip, iv., p. 171, 
fig. 64) I had not seen any specimen, and was obliged 
to copy Lieut. -Colonel Godwin-Austen's desciiption 
and figures, in which no indication is given of the 
palatal armature. :\Ir. W. T. Blanford has oblig- 





Fig. lO^.—PlccioJiylis fcddeni. 

ingly allowed me to examine the type specimens 
which are in his collection, and I am now able to 
supplement the figures already published with a view 
of the palatal armature and one of the parietal 
armature of an immature shell. The shell of which 



SCIENCE-GOSSIP. 



77 



the parietal armature was figured has the outer 
wall of the last whorl broken away ; in a second 
specimen — not quite mature — this portion of the 
outer wall is also missing ; the upper horizontal 
fold in the latter specimen is very short, and the 
third (anterior) transverse fold has not been formed 
{see fig. iOi\b). A third specimen is entire ; but, as 
the shell is somewhat translucent, I was enabled by 
wetting it to make out the conformation of its 
palatal armature without much difficulty, and 
the figure I have given of it represents 
these structures as they would appear if 
looked at from the inner side (see fig. 104a). It will 
be seen that the first (upper) fold is almost horizontal ; 
the second is longer, a little deflected posteriorly, 
where it is also attenuated, but truncated anteriorly ; 
the third is shorter, oblique, curved ; the fourth sub- 
vertical, bilobed at its middle, and furnished on the 
posterior side with two small denticles, one near its 
middle, and one near its lower extremity ; the fifth is 
sub-horizontal, and has its two extremities a little 
deflected ; a little denticle occurs near its posterior 
extremity. From these features, hitherto unrecorded, 
it will be seen that this species belongs to the group 
of P. ponsonbyi, its nearest ally being P. leucochila 
(Science-Gossip, iv., p. 231, fig. 66). Since the 
foregoing remarks were written, I have been so for- 
tunate as to acquire a specimen of P. feddetii, appar- 



ently communicated by Mr. Hungerford to Mr. 
Langdon. This specimen, also, has only two trans- 
verse parietal folds, so that it is somewhat uncertain 
whether the third (anterior) transverse fold is of any 
diagnostic value. 

Plectopyhs shauensis (fig. 105.) (See Science- 
Gossip, iv. , p. 36, fig. 48). I append a figure acci- 




Fig-. 105. — Plectopyhs shanensis. 
dentally omitted, giving a view of the shell, with ]art 
of the outer wall removed, exposing the parietal 
armature. 

Mr. Ponsonby has drawn my attention to an erron- 
eous statement on page 17, with regard to his speci- 
men of P. biciliata which, he informs me, was not 
collected by Mr. Collett, but came from the Morelet 
Collection, labelled as from Neville. 

All known forms of Plectopylis have now been con- 
sidered ; and I propose to conclude this series of papers 
with a synopsis, a key to the species, a map showing 
their geographical distribution, and a general index. 
t^To he continued.) 



SCIENCE-GOSSIP. 



147 



ARMATURE OF HELICOID LANDSHELLS 

AND 

NEW SECTIONS OF PLECTOPYLIS- 
By G. K. Gut>E, F.Z.S. 

{Contimicdfrom p. 77. j 



n~*HE genus Plectopylis was established by Mr. 
■*■ Benson in the " Annals and Magazine of 
Natural History" (3), v., (i860), p. 244, and in the 
preceding volume of the same publication (3), iv. , 
(1859), p. 95, he described the external characters of 
the animal of P. aihatiiia. Mr. Sloliczka, however, 
was the first to examine some species anatomically 
(Journ. Asiat. Soc. Bengal, 1871, p. 217), the forms 
investigated by him being P. achatina, P. cydaspis, 
P. pinacis, and P. iiiacromphalus. He states that on 
the whole the form of the body closely resembles that 
of Clausilia, and that a comparison of the interior 
organisation of the two genera also indicates their close 
relation. On comparing the jaw of Plectopylis with 
that of Clausilia, he found both similar in structure, 
but the shape different and the transverse sulcation 
only indicated in the latter genus. Much greater, he 
continues, is the similarity of the Plectopylis jaw with 
that of Cylindrella, with the exception that the 
median projection is wanting in the Cylindrella jaw. 
The arrangement of the teeth of P. achatina and P. 
cydaspis he also found to agree with that of 
Cylindrella in the very small size of the centre tooth, 
but this was not found to be a constant character. In 
/'. pinacis the centre tooth was larger and more of a 
shape similar to that of the lateral teeth, which, how- 
ever, in all the species he found to retain distinctly 
the helicoid character. 

The true systematic position of Plectopylis still' 
seems uncertain. Mr. Pilsbry doulttfully places it in 
the family Helicidae — between the groups Macroogona 
and Teleophallogona (Manual of Conch, ix.. Index to 
the Helicidae, 1895, p. 124). He includes two 
Chinese groups of uncertain affinities, Traumatophora 
Oct , 1899.— No. 65. Vol. W. 



and Stegodera, each containing one species, but as 
nothing is known of their anatomy, and as, moreover, 
they are devoid of the armature characteristic of 
Plectopylis, I consider it expedient, for the present, to 
exclude them. 

The shells of Plectopylis are characterised by a more 
or less depressed discoid form, with a flat or conical 
spire and a large open umbilicus (narrow in the section 
Sykesia), the upper surface is usually sculptured with 
spiral lines, and the immature shells are hirsute. The 
aperture is semi-circular or lunate, the peristome 
somewhat expanded and generally thickened, its ends 
usually united by an elevated ridge on the parietal 
callus, which has often an entering fold. The arma- 
ture consists of a vertical or transverse plate or plates 
with accessory horizontal or oblique folds on the 
parietal wal! ; and transverse, horizontal or oblique 
folds and denticles on the palatal wall. " When the 
animal retracts into its shell, the passage through the 
folds is generally found to be filled up with mucous 
secretion, but the body itself mostly retracts o:ie-half 
of a whorl further inwards. During hibernati m the 
aperture is besides closed with the usual caU ireous 
lamina, as in the other Helicidae." (Stoliczka, lourn. 
Asiat. Soc. Bengal, 1871, p. 218). 

Mr. Benson noted that Plectopylis achatina was 
ovo-viviparous, and this was found to be the case with 
all the species examined by Mr. Stoliczka. One 
specimen of P. cydaspis he found to contain three 
well-developed embryos, each consisting of three 
convolutions, regularly coiled in and enclosed in a 
thin soft sac of calcareous granules, loosely joined 
together. I have also observed this fact in a specimen 
of/", lissochlai/iys in Mr. Fulton's possession. 



148 



SCIENCE-GOSSIP. 



Mr. Benson divided the genus into three sections ; 
the typical section comprising P. ackatina and 
P. cyclaspis ; the second section consisting of P. refiiga 
and P. Iciophis, while the third section contained 
P. plectostoma and P. piiiacis. The great number of 
species discovered since Benson's time necessitates 
still further division, antl I propose the following 
synopsis. 

I. Section Endothyra, n. sec. Type P. plecto- 
stoma. (Third section of Benson). Sinistral. Umbilicus 
moderate. Palatal folds horizontal or oblique. 

Habitat : Sikkim, Assam, Burma. 

1. P. minor, G.A. Darjeeling, Sikkim ; Naga 
Hills, Assam. 

2. P. hanleyi, G.A. Sikkim. 

3. P. blanda, Gude. Naga Hills. 

4. P. macromphalus, W. Blf. Darjeeling ; Khasia 
Dafla and Naga Hills. 

5. P. sowerbyi, Gude. Khasia Hills. 

6. P. plectostoma, Bens. Darjeeling, Sikkim ; 
Dafla Khasia and Naga Hills, Sylhet, Kohima, 
Assam ; Cherra Poonjee, Munipur ; ;Bassein, 
Arakan. Pegu. 

prodigiuni, Bens. 

V. tricarinata, Gude. Khasia Hills. 

7. F. affinis, Gude. Khasia Hills. 

8. P. pinacis, Bens. Darjeeling, Bungmaval, Sikkim. 

pettos, Mts. 

9. P. fultoni, G.A. Khasia Hills. 

H. Section CHERSAECtA, n. sec. Type P. hiophis. 
(Second section of Benson). Sinistral or dextral. 
Umbilicus wide. Palatal folds horizontal or oblique. 
Sometimes with one oblique or vertical plate. 

Habitat : from Assam through Upper Burma and 
Laos to Tenasserim. 

10. P. muspratli, Gude. Naga Hills, Assam. 

11. P. austeni, Gude. Diyung Valley, Singpho, 
Assam. 

12. P. oglei, G.A. Sadiya, Assam. 

13. P. serica, G.A. Naga Plills. North Cachar. 

sericata, Hanley and Theob. 

14. P. munipurensis, G.A. Munipur. N.E. 
J'rontier, Bengal. 

15. P. nagaensis, G.A. Naga Hills. 

16. P. pseudophis, VV. Blf. Thayat Myo, Pegu. 

17. P. leiophis, Bens. Thayet-Myo, Kivadouk, 
Akoul Dung, Pegu. 

refuga, auct. 

18. P. refuga, Gould. Tavoy, Tenasserim. Pegu. 

19. P. perrierae, Gude. Thayet-Myo, Pegu. 

20. P. shiroiensis, G. A. Shiroifurar, Munipur. 

21. P. perarcta, W. Blf. Mya Leit Doung, Ava. 
Hlaindet, Upper Burma. 

22. P. brachvdiscus, G. A. Moulmain, Tenasserim. 

23. P. dextrorsa, G. A. Tenasserim. 

24. P. shanensis, Stol. Pegu ; Shan states. 

trilaniellaris, G. A. 

25. P. brahma, G. A. Brahmakhund, E. Assam. 

26. P. andersoni, W. Blf. Bhamo, Ava, Upper 
Burma. Hoetone, \'unnan. 

27. p. iaomontana, Pfr. Luang Prabang, Laos. 



HI. Section Endoplon, n. sec. Type P. 
brachyphda. Dextral. Palatal folds horizontal, 
oblique, or almost vertical. 

Habitat : Tonkin, Burma. 

28. P. smithiana, Gude. Attaram, Burma. 

29. P. Ijrachyplecta, Bens. Moulmain. 

30. P. giardi, H. Fischer. Cao-Bang, Tonkin. 

31. P. congesta, Gude. Tonkin. 

32. P. franc^oisi, H. Fischer. Deo-Ma-Phuc, Tonkin. 

33. P. jovia, Mab. Halong, Tonkin. 

34. P. schlumliergeri, Morlet. Halong, Elephant 
Mountain, Nuy- Dong-Nay, Tonkin. 

35. P. villedaryi, Ancey. Lang-Son, Bac-Ninh, 
Tonkin. 

36. P. phlyaria, Mab. Tonkin. 

IV. Section Plectopylis, s. s. Type P. aihatiiia. 
(Typical section of Benson). Sinistral. Shell 
flattened. Palatal armature : one vertical plate with 
three horizontal folds above, one below. 

Habitat : Burma. 

37. P. ponsonbyi, G.A. Hlaindet, Burma. 

38. P. lissochlamys, Gude. Moulmain. 

39. P. magna, Gude. Moulmain. Taunghu, Pegu. 

40. P. woodthorpei, Gude. Fort Stedman, Burma. 

41. P. leucochila, Gude. Burma. 

42. P. feddeni, W. Blf. Prome, Pegu. 

43. P. cairnsi, Gude. Burma. 

44. P. cyclaspis, Bens. Moulmain ; Tenasserim. 

catimis, Bens. 
revoluta, Pfr. 

45. P. karenorum, W. Blf. Arakan Hills ; Hen- 
zada ; Pegu. 

burniaiiica, Bens, M.S. 

46. P. linterae, Mlldff. Pegu. 

v. fusca, Gude. 

47. P. anguina, Gld. Tavoy, Tenasserim. 

48. P. achatina, Gray. Moulmain ; Tavoy. 

V. repercussoides, Gude. Burma. 

v. infrafasciata, Gude. Moulmain. 

V. castanea, Gude. Burma. 

V. obesa, Gude. Moulmain. 

V. venusta, Gude. Burma. 

pachystoma, Theob. M.S. 

V. breviplica, Gude. Burma. 

49. P. repercussa, Gld. Moulmain. Tavoy. 

V. Section Simcola, n. sec. Type P. Jit/ibriosa. 
Dextral, Palatal folds horizontal. 

Habitat : China ; Tibet i species. 

50. P. emoriens, Gredl. Hoo-Nan. 

51. P. azona, Gredl. Badung, Hoo-Pe. 

52. P. pulvinaris, Gld. Canton ; Hongkong. 

53. P. fimbriosa, Mts. Kiang-Si. 

v. nana, Mlldft". 

V. continentalis, Mlldft". 

54. P. reserata, Heude. Tchen-Keou. Badung 
Hoo-Pe. 

55. P. laminifera, Mlldff. Hoo-Pe. 

56. P. jugatoria, Anc. Kouei-Tchou. 

57. P. diptychia, Mlldft'. Kouei-Tchou. 

58. P. biforis, Heude. Ta-Kouan-Tchen. 

59. P. stenochila, Mlldff. Hoo-Pe. 

V. basilia, Gude. Badung, H00-P6. 



SCIENCE-GOSSIP. 



149 



-60. p. alphonsi, Desh. Moupin, E. Tibet. 

61. P. murata, Heude. Tchen-Keou. 

62. P. cutisculpta, Mlldff. Fud-Shien. 

63. P. invia, Heude. Tchen-Keou. 

64. P. secura, Heude. Kouang-.Si. 

65. P. multispira, Mlldff. Hoo-Nan. 

66. P. schistoplychia, Mlldff. Hoo-Nan. 

67. P. vallata, Heude. Tchen-Keou. 

VI. Section Exteroi'lax, n. sec. Type /'. 
ijiiadrasi. Dextral. 

Habitat : Philippine Islands. 

68. P. trochospira, Mlldff. Cebu ; Siquicir. 

V. boholensis, Gude. Bohol. 

69. P. quadra^i, Mlldff. Luzon. 

70. P. polyptychia, Mlldff. Cebu. 

VH. Section Sykesia, Gude (1897), Science- 
Gossip, N.S. iii., p. 332. AusTENiA, Gude ib., 
p. 300, pre-occupied by Nevell (1878). Type, P. 
clathratiila. Dextral, shell translucent, acutely keeled. 

Habitat : Southern India. Ceylon. 

71. P. retifera, Pfr. Nilgiri and Shevroi Hills, 
So. India. 

72. P. clathratuloides, (iude. Anarmalai Hills, 
So. India. 

73. P. clathratula, Pfr. Ceylon. 

pziteohis, Bens. 
puteolus, Bens. 
V. compressa, Sykes. Ceylon. 

74. P. caliginosa, Sykes. Ceylon. 

75. P. biciliata, Pfr. Ceylon. 



I strongly suspect that when the anatomy of the 
Philippine species (Section Enteroplax) is investigated 
the group will be found to differ so widely from 
typical Plectopylis Xh'ax it will have to be raised to the 
rank of a separate genus. The same may prove to be 
the case with the section Sykesia. It is somewhat 
difficult to hazard an opinion as to the primordial 
form from which the present species of Plectopylis 
have been evolved as no fossil forms are known, and 
likewise it is almost impossible to judge as to 
which of the known forms are the most archaic, 
for the armatures of immature specimens, as 
far as they have come under my observation, 
throw no light on the subject, as they did in the case 
of Gorilla (c.f. Science-Gossip, N.S. iii., 1896, p. 
128) ; except in size and in the lengths of the folds, the 
barriers of mature and immature shells of Pk-ctopylis, 
are almost identical. There is one exception in this 
respect, i.e., Plectopylis zvoodthorpei, in which, as I 
pointed out {ante p. 16), the palatal folds of the 
anterior series are only found in mature shells. It 
may, however, be assumed that the simple armatures 
preceded the more complicated, and on this assump- 
tion 7'. aikatiita and its allies, with their complex 
parietal barriers, must be regarded as the most 
recent ; while in another direction, P. plectostoma 
and its congeners, with their biserial palatal folds, 
have presumably been evolved from some monoserial 
predecessor, of which P. sowerhyi may be taken as a 
less modified representative. 

{To he concluded.) 



174 



SCIENCE-GOSSIP. 



ARMATURE OF HELICOIlJ LAXUSHELLS. 



By G. K. GuDE, F.Z.S. 
(Concluded from page 149.) 



A^yTTH regard lo the geographical distribution, as 
far as our present ivnowledge enables us lo 
judge, the genus is confined to Sikkim, Assam, Further 
India and China, extending south to Tenasserim, 
north as far as Central China, west to Sikkim, and 
east to Tonkin, with two outlying groups : one in the 
southern extremity of the Indian Peninsula and Ceylon, 
the other in the Philippine Islands. 

On looking at the accompanying map, where I have 
indicated all the known species at their respective 



believe, who has traversed this region, informs me he 
collected forms of Pleclopylis there, but I have not 
yet been able to inspect them. Crossing the Hima- 
layan Range we find one species in Eastern TiV^et, 
P. alpkousi, while China, including Hongktjng, has 
no less than seventeen species. A wide gap 
separates the Sikkim forms from the South Indian 
and the Cingalese species, a fact which \vill be less 
surprising, if, as I suspect, the latter prove to belong 
to a distinct genus. In all probability further 




Map, showing Distribution of Genus Plectopvlis. 



habitats, some curious and striking facts in the distri- 
bution of the genus Plectopylis become apparent. It 
will be seen that the centre of distribution appears to 
be Lower Burma, especially Pegu and Tenasserim ; 
while no species occur to the south-east, the whole 
of Siam and Cochin China being blanks. Going east 
the Burmese Shan States and Laos each possess one 
species, P. shanensis and P. laomontana respectively, 
while Tonkin has eight. Upper Burma contributes 
one species from the Bhamo district, P. andersoni, 
one from Munipur, P. mmiipitrensis , and 
three species in the south, i.e., P. perarcta, 
P. ponsonhyi, and /'. woodlhoipei. Assam has 
fourteen species. Going west we find another blank 
till we reach Sikkim, the western limit of the genus, 
where there are five species. The intervening 
country, Bhutan, has scarcely been explored, but 
Lieut. -Col. Godwin-Austen, the only naturalist, I 
Nov. 1899— No. 66, Vol. VI. 



exploration will bring to light many additional 
species, and possibl)^ both Siam and Cochin China 
will, when they are searched diligently, be found to 
posse.ss some interesting forms of the genus. 

On page 149 I stated that no fossil forms of Plecto- 
pylis are known. I omitted to «iention, however, 
that Dr. Stoliczka described three species of fossil 
Helices, which he referred to the section Anchistoma 
= Gonostoma, stating that they had affinity with 
Plectopylis and Gorilla. (Cretaceous Fauna of Southern 
India, II., p. 9 et. sec/.). Mr. Nevill, who examined 
the.se fo.ssil shells, on the other hand, was of opinion 
that iheir appearance did not warrant this theory. 
(Journ. A.siat. Soc. Beng. L., 1S81, p. 128). 

I append a key lo the species which I venture lo 
hope will prove serviceable ; and. Um convenience of 
reference, I have added an index. 



SCIENCE-GOSSIP. 



175 



^. 



/•nuicis. 
sozverbyi. 
fultoni 
macron! pJiahis 



I'landa. 
minor. 

hanlcyi. 



plectostoiiui. 



I. Section Endothyra. 

A. Palatal folds in one series. 

a. Shell 14-15 ni.m. horizontal fold below 
parietal plate 

b. Shell not ex'ceeding q ni.m. horizontal 
fold absent 

B. Palatal folds in two series. 

a. Parietal plate without denticles 

b. Parietal plate with one denticle pos- 
teriorly 

c. Parietal plate with two denticles posteriorly 

(X. Shell not exceeding- 6 m.m. 

* One upper and one basal palatal fold, 
t A short horizontal fold above 
parietal plate . . 
tt horizontal fold none 

* * Only one basal palatal fold 
shell 8-10 m.m. 

* Parietal plate gives oft' anteriorlx- a 
horizontal fold from upper extremity ; 
one short horizontal fold below 

* * No horizontal foldproceeding-froni 
parietal plate ; two short horizontal 

folds below.. .. .. .. . nffinis. 

II. Section Chersaecia. 
I. Dextral. 

A. Transverse parietal plate simple. 

a. Free horizontal parietal folds none. 
a. Palatal folds six. 

Connected by a transverse ridge ; 
shell 27 m.m. .. .. oglii. 

** Not connected ; shell 24-26 m.m. . nndcrsoni. 
). Palatal folds7?r'(>; shell 11 m.m. .. serica. 
"y. Palatal folds .wt'ch with two denticles lao)iiontami. 

b. A tree interrupted horizontal fold in 
front of parietal plate; palatal folds si.x, 
four inner united by a vertical ridge, 

seven denticles posteriorly . . . . an.stetii. 

B. Transverse parietal plate- giving oft 
anteriorly above a short horizontal fold, with 
a denticle below plate. Palatal folds six; 

shell lo-ii m.m. .. .. .. .. miiui/iuroisis. 

C. Transverse p2rietal plate giving oft' 
anteriorily bf/av a long horizontal fold. 

a. With a median horizontal fold con- 

timious to the peristome ; shell 20 m.m. . . bracltydiscus. 

b. With a median horizontal fold /«- 
tcrrvpted; shell 16 m.m. .. .. .. dextrorsa. 



/3. 



2. SiMSTRAT.. 



Parietal plate simple. 
a. Horizontal fold 
parietal plate, short. 
0,. No median fold . 



below transverse 



/3. 



5. A long- median fold present. 
~' A third short horizontal told be- 
tween upper and lower parietal folds. 

+ Palatal folds, all horizontal, shell 

10 m.m. . . 

tt Palatal folds, one \ertical, rest 

horizontal ; shell 7.5 m.i-n. . 
** No third fold present 

b. Horizontal fold below transverse parie- 
tal plate long-, joined to apertural ridge 

c. Three short horizontal folds in front 
of transverse parietal plate, none below it 

B. Transverse parietal plate giving oft' 
anteriorly below a short horizontal fold ; a 
long median and a long lower fold present, 
joined to apertural ridge. 

a. Palatal folds : all horizontal 

b. Palatal folds : one oblique, rest hori- 
zontal. 



musp7-atti. 



pcrarcta. 

shii-oiensis. 
nagnensis . 

perricrac. 

re/itga. 



shanensis. 



CI. Parietal plate rounded in outline . . Uiophis. 

p. Parietal plate /()oi'/;(-^/ in outline .. pseudophis. 
C. Transverse parietal plate giving oft' an- 
teriorily below a short horizontal fold, two 
short free horizontal folds above the latter, 
and a long one below joining the apertural 
ridg-e brahiun. 

III. Section Exnopi.ON. 

A. Shell flattened. 

a. Armature unknown phlyaria. 

b. T«o vertical parietal plates . . . . bracliyplecta. 

c. One %ertical parietal plate with two 
denticles in front sinithiana. 

B. Shell with more or less conical spire. 

a. One transverse parietal plate. 

O. One denticle in front of parietal plate. 
Parietal plate rciunded in outline ; 
shell not exceeding 26ni.m. . . scJduiiibergeri 

Parietal plate toothed in outline ; 
shell, 30 m.m. . . . . jo7<ia. 

fj. Two denticles in front of parietal 

plate villedaryi. 

b. Two transverse parietal plates. 
U. One horizontal parietal fold. 

'■' above anterior plate . . . . . . giardi. 

' ^' below both plates . . . . . . congestn. 

p. Two horizontal parietal folds, one 
above, one below, the latter joined to 
the two transverse plates . . .. .. /ran^oisi. 

l\. Section Pi.ectopyi.is, s.s. 

A. Two transverse parietal plates. 

a. Parietal plates parallel ; upper hori- 
zontal palatal fold bisected. Shell less 
thano m.m. 

U. Median parietal told truncate, not 
joined to apertural ridge . 

|0. Median parietal fold not truncate, 
joined to apertural ridge . . 

b. Parietal plates divergent ; upper hori- 
zontal falatal fold not bisected. Shell 
mc re than 20 m.m. 

c. Anterior parietal plate giving off a long 
horizontal fold above, and 

0.. A short one below, half the length ot 
upper ; palatal folds in two series 

Kj. Lower fold one-quarter of the length 
of upper ; palatal folds in one series 

B. Three trans\-erse parietal plates.. 

C. Parietal plate ramified. 

a. Shell acutelj' keeled. Parietal fold tri- 
furcate : a short horizontal fold near 
aperture . . 

b. Shell not keeled. Parietal fold tri- 
furcate. 

(X. No horizontal fold below parietal 
plate, a free interrupted horizontal fold 
in tront 

p. Parietal fold gi\ ing off anteriorly an 
interrupted horizontal fold ; a short 
horizontal fold below plate 

v. Parietal fold giving oft" anteriorly a 
continuous fold 

« Shell thin 

** Shell thick. 
+ Upper arm of parietal fold 
longest, lower horizontal fold united 
to apertural ridge 

tt Lower arm longest, lc>wer hori- 
zontal fcild not united to apertural 
ridge. 

\ Whorls much flattened, umbili- 
cus very shallow 

(SJ Whorls less flattened, umbilicus 
deeper . . . . 



ponsonhyi. 
lissocldaiitys. 



ivoodthorpez 

lemochila. 
feddcni. 



cyclnspis. 



I interne. 



karenoruln. 



repi'reiis.^a. 



nngiiina. 
acltatina. 



176 



SCIENCE-GOSSIP. 



/3. 



/3. 



\'. Section SiNlcoi.A. 

A. Armature unknown . . 



B. Two transverse parietal plates. 

a. Shell 6 m.iii. . . 

b. Shell 16 m.m. 

C. One transverse parietal plate. 

a. Parietal denticles or folds none. 

U. Palatal folds in one series, parietal 
horizontal fold at aperture. 

* Shell 6.5 m.m. . . 
^** Shell 9 m.m 

Palatal folds in two series 
No horizontal fold at aperture. 

b. Two parietal denticles anterior to 
transverse plate. 

OL. Whorls angular or keeled, palatal 
folds six. 

* Whorls 4j, shell notexceedingf 7 mm. 
** Whorls'e. 

t Shell 15 m.m. . . 
++ Shell 12 m.m. 

Whorls rounded, palatal folds 7 

c. Two parietal denticles posterior to 
transverse plate 

d. One or two horizontal folds in front ot 
parietal plate. 

O. Shell acutely keeled. umbilicus 
moderately deep ; two vertical denticles 
between folds 

lO. Shellangulated, umbilicus very deep ; 
one horizontal denticle between folds . . 

e. Two short horizontal folds in front of 
parietal plate, with one to four denticles 
between. 

Ct. Shell conical above, 62 — 7 whorls. 
* Whorls rounded 
Whorls keeled 
Shell depressed, 5.? — 6 whorls 

f. One short horizontal fold above, with 
four or five denticles below, in front of 
parietal plate ; shell shining-, pellucid 

VI. Section Enteroi'lax. 

A. Palatal folds : /our. 

a. Horizontal parietal folds united by a 
vertical ridge posteriorly 

b. Parietal folds not united . . 
Umbilicus moderate .. 



j'ttzatoria. 

alphonsi. 

vnllata. 

dif'ty cilia, 
hi/'cris. 



mvia. 
si'ctifa. 



schistoptychia 



13. 



eiiioneiis. 

Jiiiil'riosa. 

azona. 

puh'inaris. 

cutiscidpta. 



reserata. 
laniiiii/era. 



stcnochila. 
V. basilia. 
tinirnta. 



iiniltispira. 



a. 

p. Umbilicus narrower . . 

B. Palatal folds : ten 

\'II. Section Svkesia. 

A. One transverse parietal fold. 

a. Notched about the middle, a short sup- 
port posteriorly above. Ceylon. 

(1. Umbilicus wide ribs and lyrae 
prominent 

p. Umbilicus narrower ribs and lyrae 
obsolete 

b. Not notched. 

U. Straight, without support, umbilicus 
still narrov.er. Habitat, India . . 
p. Sinuous, with a short support an- 
teriorly above ; umbilicus still narrower. 
Habitat, India 

B. Two transverse parietal plates. 

a. Shell flattened, no fold below umbilical 
angulation, umbilicus still narrower, 
Habitat, Ceylon 

b. Shell conoid, with a double fringe of 
curved hairs; a horizontal fold below 
umbilical angulation ; umbilicus still 
narrower. Narrowest of all. Hab.. Ceylon 



qiiadrast. 

troc/iosptra. 

V. hohohnsis. 

polyptychia. 



clathraiida. 
\. conip7-essa. 

rla th vatuloidcs. 

retifcra. 

cn/iginosa. 

hiriliiita. 



V. 
V. 
V. 
V. 
V. 
V. 



Index 'jo Plectopylis. 

The roman figures after the names indicate the volume 
of SciKNCE-GossiP New Series, page is in ordinary type, and 
number of figure is in italic type. 

achalina. v., 114. So, Sr, S'2. 

bieviplica, v., 134, Sj. 

castanea, v., 134, S6. 

infrafasciata, v., 133, S4. 

obesa, v., 115, Sj. 

repercussoides, \-. , 333. 

venusta, v., 134, 8j. 
affinis, iii., 276, .//. 
alphonsi, v., 239, g^. 
andersoni, iii., 154, ry. 
anguina, v., 76, 79. 
austeni, vi., 15, 97. 

AUSTEN/A, I/I., 300, 332, r/., 149. 

azona, iii., i8o, 204. 

biciliata, vi., 16, gg. 

biforis, iv. , 103, 57, 

Ijlanda, iv., 264, yo. 

brachydiscus, iii., 154, iS. 

biachyplecta, iii., 246, 77. 

brahma, iv. , 170, 6j. 

hiirijiaiiica, iii, 245. 

caiin.si, v., 171, go. 

caliginosa, vi., 75, 100. 

cat inns, iii., 244. 
Chersaecia, VI., 148. 

clathratula, iii., 300, 42. 
V. compressa, vi., 75, loi. 

clathratuloides, iii. 332, 44. 

congesta, v. , 332, gb. 

cutisculpta, iii., 180, 6. 

cyclaspi.s, iii., 244, j^ 

dextrorsa, iii., 156, 21. 

diptychia, iv., 2S4, 7/. 

emoiiens, iv. , 36, 50. 
Endoi'LON, VI., 14S. 
Endothyra, VI., 148. 
Enteroplax, VI., 149. 

eugeni, v., 172, g2. 

feddeni | '\"-' 7^' ^^• 
I VI., 76, 104. 

fimbrio.sa, iii., 179, 24. 

V. nana, iv. , 180. 

fran9oisi, vi., 75, ro2. 

fultoni, iii., 178, 2^. 

giardi I ^V 332, 95- 
^ \ VI., 76, IPS- 

hanleyi, v., 240. 

( 181, 28. 

invia, ni. 

• 204. 

jovia, iv., 138,59. 

jugatoria, v., 240. 

karenorinn, iii., 244, y. 

lacythis ( Nanina), v., 115. 

lamcabensis, v., 171, gi. 

larninifera, iii. , 204, jo. 

laomontana, iii., 245, 76. 

leiophis, v., 16, 76. 

leucochila, iv. , 231, 66. 



SCIENCE-GOSSIP. 



1/7 



linterae, v., 170, 88. 

V. fusca, v., 170, 8g. 
lissochlaniys, iv. , Jo, JJ. 
niacromphalus, iv., 10, 46 
magna, iv. , 70, ^2. 
minor, iv. , 11, ^7. 
muliispira, iii., 181, 27. 
munipurensis, iv., 263, 6g 
murata, iv., 284, J2. 
muspratli, iv., 10, 45. 
nagaensis, iii., 206, jj. 
oglci, iv. , 263, 6S. 

pachystoina, v. ■ ~^'^' 
^ -^ ' I 170. 

perarcta, iii., 155, ig. 

perrierae, iv., 231, 67. 

pcltos, iii., 206. 

plilyaria, iv., 139, bi. 

pinacis, iii., 206, J2. 

Plectopyi.is, S.S., VI., 148. 

plectostoma, iii., 274,^9. 

V. tricaiinata, iii., 275, 40. 

polyptychia, iv., 102,55. 

pon.sonbyi, iii., 178, 22. 

] , • ) iv. 170, 62. 
pseudophis j ^._ ^^^ ^^_ 

pulvinaris, iii., 180, 25. 

V. continentalis, iii., 180. 
puteola, iii., 300. 
quadrasi, iv., 71, J^/. 
refuga, v., 15, 75. 
repercussa, v. 74, yS. 
reserata, iv. , 37, J/, 
retifera, iii., 301, 43. 
revoluta, vi., 76. 
schistoptychia, iv., 102, j6. 
schlumbergeri, iv. , 138, ji?. 
secura, iv., 231, 65. 

?/• 



serica, in. 
sericata, iii., 205 



( 205, J. 
1246. 



shanensis \ ■"' tJ 

\ VI., 77, 103. 



, 155, 20. 

shiroiensis, in., -'-' 

I 204. 

SlNICOLA VI., 148. 

smitliiana, iii., 274, 3S. 

sowerbyi, v., 239, gj. 

stenochila, iii., 204, 2g. 
V. basilia, iv., 36, 4g. 
Sykesia, III., 332, vi., 149. 

trila'/iellaris, iv., 36. 

trochospira, iv. , 285, 7j. 
V. boholensis, iv., 285, J4. 

"rallala, v., 240. 

villedaryi, iv., 139, bo. 

woodthorpei, vi., 15, gS. 
\ i^U\ '\co\:i.c\\.\A\ng this consideration of the genus 
PlectopyUs, I desire to acknowledge my indebtedness 
to many friends and correspondents vvitliout whose 
ung;rudgirvg assistance I could not have proceeded 
with the task. To Mr. Ponsonby I owe an irre- 
deemable debt of gratitude, for in addition to valuable 



advice and suggestions, he has placed his unrivalled 
collection at my disposal. Lieut. -Col. Godwin- 
Austen, Mr. Edgar Smith, and Mr. S. I'". Harmer 
have also placed me under deep obligation ; the 
first-named communicated undescribed material, and 
all have allowed me access to type specimens. 
Miss Linter has very obligingly presented me with a 
series of shells, some of which proved to be new, 
while finally — for the loan of specimens from their 
collections, or from collections under their charge — 
I have to thank Prof. Boettger, Col. Beddome, the 
Rev. R. A. Bullen, Mr. W. T. Blanford, Mr. Robert 
Cairns, Mr. W. E. Collinge, the Rev. Vincenz 
Gredler, Mr. II. Fulton, Dr. H. Fischer, Prof. 
Giard, Mr. E. L. Layard, Mr. Jules Mabille, Prof, 
von Martens, Dr. von Mollendorfi', Dr. F. J. H. 
Merrill, Mr. E. R. Sykes, and Mr. G. B. Sowerby. 
To the Editor of Science Gossip, I am also 
greatly indebted for his unremitting courtesy, attention 
to details, and for aftbrding space in the pages of this 
Magazine, frequently, I fear, to the exclusion of matter 
more interesting to the general readers. 
Adelaide Road, London, N. IV. 
2)id September, iSgg. 



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