224 THE ORIGIN OF VERTEBRATES 
Croneberg’s observations and conclusions are distinctly of very 
great importance in bringing the arachnids into line with the crus- 
taceans, and it is therefore most surprising that they are absolutely 
ignored by Lankester and Miss Beck in their paper published in 
1883, in which Latreille only is mentioned with respect to this 
organ, and his term “camerostome,” or upper lip, is used throughout, 
in accordance with the terminology in Lankester’s previous paper. 
That this organ is not only a movable lip or tongue, but essentially 
a sense-organ, almost certainly of smell and taste, as follows from 
Croneberg’s conclusions, is shown by the series of sections which I 
have made through a number of young Thelyphonus (Fig. 102). 
es 
Hyp ~ post ent 
Olf pass — 
Fic. 96.—Mzxpian SaGitraL SECTION THROUGH A YOUNG THELYPHONUS. 
‘ 
i 
, 
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I give in Fig. 96 a sagittal median section through the head-end 
of the animal, which shows clearly the nature of Croneberg’s con- 
ception. At the front end of the body is seen the median eye (ce.), 
o is the mouth, Ph. the pharynx, es. the narrow cesophagus, com- 
pressed between the supra-cesophageal (supr. ws.) and infra-cesopha- 
geal (infr. ws.) brain mass, which opens into the large alimentary 
canal (Al.); OUf. pass. is the olfactory passage to the mouth, lined 
with thick-set, very fine hairs, which spring from the hypostome 
(Hyp.) as well as from the large conspicuous camerostome (Cam.), 
which limits this tube anteriorly. The space between the came- 
rostome and the median eye is filled up by the massive chelicere, 
which are not shown in this section, as they begin to appear in the 
