9 o 



NEW YORK STATE MUSEUM 



[ 1 898, p. 5 1 8] in Diplograptus appendiculatus Tornq. ms, i n 



regard to which it is stated : 



From the upper end (of the rhabdosome) proceeds the vesicle, inside 

 of which the virgula can quite well be detected [see text fig. 23]. 



The present writer observed a " cucumber-shaped " expansion of the 

 nemacaulus [1904, p. 722, pi. 16, fig. 2, 3] in Diplograptus lax us 

 (lateral view of Cryptograptus antennarius, see under Cryptogr.). 



I have before me, besides Gurley's material of the 

 vesicles of Climacograptus p h y 1 1 o p h o r u s and 

 C. caelatus, a very large collection of finely preserved 

 vesicles of the former in all stages of development from the 

 Normanskill shale at Glenmont, and those of Crypto- 

 graptus antennarius and tricornis. This 

 materia], it seems to me, permits some observations of 

 Fig. 23 Dipiograp- interest on account of its bearing on the structure and 



tus appendiculatus o 



Tornquist manuscript. r . r , . , ,, 



copy from Eiies function ol the vesicles. 



We have noted in the foregoing quotations that the English authors 

 have unhesitatingly termed these appendages "vesicles" 

 without, however, entering upon a discussion of their possi- 

 ble function. Gurley on the other hand has pointed to the 

 bilateral symmetrical form and flat leaflike appearance of 

 the appendages in the two specimens of Climacograptus 

 and designated them as "disks." 



The features observable in our specimens, to which we 

 would direct attention, and the resulting inferences, are : 



1 The "virgula" passes distinctly through the append- 

 ages, as Elles has pointed out in regard to Diplograp- 

 tus appendiculatus. The large appendages of the 

 species of Climacograptus here noted show the same feature, 

 and frequently the rod extends beyond the expansion and Fi - m en,,..-,. , ; . 



1 J J -i graptus parvus Hall. 



dl 1 .1 • .1 ]• .• . 1 1 r ._ r ~l H^\ Dilatation with virgula in 



s bluntly with a distinct break [see text lig. 24 |. Iney medianiine. k S 



are further found in all stages of development from narrow lanceolate 



