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NEW YORK STATE MUSEUM 



extremely delicate multiramous dichograptid, but owing to their flexible 

 nature the branches of the rhabdosome have, even by a very gentle cur- 

 rent, nearly always been drifted into an inextricable mass; and, as at the 

 same time innumerable specimens are piled together, it was found impos- 



43a 



Fig. 43 G o n i o M' I' a p t u s g e o m e t r i c u s sp. nov. a Sicula and proximal parts of first two thecae. 

 Shows nema, which has become too thick in the zincograph. x8; b Growth stage with two thecae, which 

 show apertural processes. x7; c Lilie growth stage, where the first theca originates nearer to the apex. 

 x7 ; (I Growth stage in which the first theca buds extremely close to the apex of the sicula and further 

 dichotomy has set in. Reverse view. x7 ; e Young rhabdosome with relatively short or fragmentary sicula. 

 Reverse view. x7 ;/ Greater enlargement of first dichotomy. x31. Deep kill 



sible to obtain specimens as well spread out as the type species of Gonio- 

 graptus has furnished. 



Description. Sicula long and narrow, needlelike, with an average length 

 of 3.5mm, but only a maximal width of .35mm; in some instances pro- 

 vided with a long, very fine nema [fig.43a]. First theca budding within 

 the apical fourth of the sicula; this and the second theca diverging at ;i 

 point one fourth of the lengtli of the sicula from the apical end in opposite 

 directions and at right angles with the sicula. These first thecae are fili- 

 form (about 2 mm long), their free portions mostly straight, but often 

 curved upv^ard. The secondary thecae (forming the branches of the second 



