628 



NEW YORK STATE MUSEUM 



extremely delicate inultiramous dichograptid, but owing to their flexible 

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

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

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



4aa *^ 



Fig. 43 GonioKraptus geometricus sp. nov. a Sicula and proximal parts of first two thecae. 

 Shows nema, whlcli lias oecome 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 ape.\ of the sicula and further 

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

 Reverse view. x7 ; / Greater enlargement of first dichotomy. x21. 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 ji 

 point one fourth of the length 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 upward. The secondary thecae (forming the branches of the second 



