FEBRUARY 16, 1912] 
If then we are to secure satisfactory paleon- 
tological knowledge of the history of holothur- 
ians.we must look for it in the impressions (or 
possibly casts) of the entire animal. As yet 
evidence of this sort is very rare and highly 
unsatisfactory. Riippell? long ago described 
what he thought was a fossil holothurian 
from the Solenhofen limestone but there is 
little about either his description or figure that 
warrants his conclusion. Zittel’ suggested 
that the object might perhaps be a cephalo- 
pod, but that is also little more than a guess. 
Giebel* has given an account, accompanied by 
three good figures, of fossils from the same 
limestones for which he proposed a genus 
“Protholoturia.” Zittel (1. ¢.) refers casually 
to this genus but considers the specimens 
“problematische kérper.” Probably he was 
not familiar with the appearance of living 
holothurians, particularly when eviscerating; 
otherwise it is hard to see why he was so 
doubtful about Giebel’s specimens. Ludwig 
(I. ¢.) quotes Zittel but apparently without 
having examined Giebel’s figures, which are 
deserving of careful consideration. Study of 
these figures and their accompanying text has 
satisfied me that the objects really are the 
impressions or casts of holothurians. Giebel 
found ecaleareous particles in the outer body 
layer (or on the surface of the object), thus 
confirming the impression made by the strik- 
ing resemblance of the outline and surface, to 
contracted specimens of the smaller species of 
Holothuria. It seems to be impossible, how- 
ever, to point out any characters by which 
“Protholoturia”” may be distinguished from 
Holothuria and the name is no doubt a syno- 
nym, but it is odd that it is not listed in 
Scudder’s Index (either as Protholoturia, 
Proholothuria or Protoholothuria) nor in the 
later generic lists of the “ Zoological Record.” 
Even Spandel and other writers on fossil holo- 
thurian remains seem to have overlooked or 
21829, ‘‘Abbildung und Beschreibung einiger 
. .. Versteinerungen . . . von Solenhofen.’? 
° 1876-80, ‘‘Handbuch der Paldontologie,’’ Bd. 
1, Abt. 1. 
*1857, Zettsch. f. die Gesammten Naturw., Bd. 
TX., pp. 385-388. : 
SCIENCE 
275 
forgotten Giebel’s work. Simonelli’ figures a 
peculiar fossil, Lorenzinia, which he suggests 
may be part of a holothurian allied to Pela- 
gothuria. The material is such that no real 
identification is possible and the probability 
of its having anything to do with holothurians 
is very remote. 
The Solenhofen specimens of Giebel there- 
fore appear to be the only fossil holothurians 
known (not counting, of course, isolated cal- 
careous particles) and obviously their phylo- 
genetic value is slight, as they simply show 
that holothurians apparently like those of the 
present day existed in the Jurassic Seas. It 
was, therefore, a matter of extraordinary in- 
terest when Dr. Walcott recently announced 
the discovery of a notably diversified holo- 
thurian fauna in the Middle Cambrian rocks 
of British Columbia. Through the greatly 
appreciated courtesy of Dr. Walcott and the 
kindly assistance of Mr. Austin H. Clark, I 
have recently had the privilege of examining 
the material upon which this report is based 
and J will say at once that Dr. Waleott’s pub- 
lished figures leave almost nothing to be de- 
sired. Excepting only two specimens, exami- 
nation of the originals showed nothing not 
revealed by the figures and equally important 
is the fact that the figures show nothing 
which is not equally distinct in the specimens. 
This is most satisfactory, as it will enable 
any one familiar with the fundamental char- 
acteristics of the class to form an intelligent 
opinion as to whether Dr. Walcott’s fossils 
represent holothurians or not. The two cases 
in which I have taken exception to the fig- 
ures are found on plates ten and thirteen. In 
Figure 1, Plate 10, the illustration does not 
quite do justice to the specimen; the knobs 
shown above the central ring (CR) are more 
distinct in the specimen, two of them showing 
not only definite outlines but some indica- 
tions of their structure. In Figure 2, Plate 
13, on the other hand, the terminal mouth 
*1906, Bologna Mem. Acc. Sc., 1905, series 6, 
Vol. 2, pp. 263-268. 
°1911, ‘‘Cambrian Geology and Paleontology,’’ 
II., No. 3, Middle Cambrian Holothurians and 
Meduse, Smithsonian Misc. Coll., Vol. 57, No. 3. 
