NO. 1873. CHARACTERS OF GIQANT0PTERI8— WHITE. 497 



shown m plate 45 and plate 48, figure 1. Wlien the lamina is 

 slightly shrunken they appear to pass, moderately strong, to the 

 border. The tertiary nerves originate somewhat regularly, at a \vide 

 angle, from the secondary nerves and also from the midribs in 

 Alethopteroid fashion. They rapidly diffuse in a somewhat fascicu- 

 late S3^stem by dichotomy into slightly divergent or nearly erect, 

 straight nervilles, some of wliich may fork again, as shown in plate 46, 

 figure 2. Similar nervilles spring directly from the secondary nerves 

 and midribs. In the older or basal portions of the large frond, 

 like that seen in plate 46, figure 2, the tertiary nerves are more 

 distinctly fasciculate; but in the liigher areas, such as that seen in the 

 nature print, figure 2, they are less divided, while near the apex, 

 plate 49, figure 4, many of the nerves are simple. 



As seen m all the figures, particularly plate 46, figure 2, plate 47, 

 figure 1, plate 48, figure 2, the nerves in each fascicle tend to 

 coalesce very obliquely with those from the next fascicle on the 

 same side, so as to form interfascicular nerves, while all the nervilles 

 of all the fascicles on one side of a secondary nerve, unless they have 

 already joined the interfascicular nerves, meet with those from the 

 near side of the next secondary nerve, and the interfascicular nerves, 

 to form a thin sutural nerve (see nature-print, pi. 48, fig. 2) which, 

 intermediate to the secondary nerves, and thin, passes, parallel to the 

 latter, completely to the margin of the leaf. The lateral union of the 

 outside nerves of the fascicule and the junction of the consequent 

 interfascicular nerve or of the remainmg nervilles with the sutural 

 nerve effects a remarkable type of very elongated, variable, and 

 angular areolation, as is imperfectly shown in plate 45, plate 47, 

 figure 1, plate 46, figure 2, and plate 47, figure 2. The position and 

 aspect of the sutural nerve reminds one of the sHghtly decurrent 

 sinus between two contiguous pinnules of Alethopteris serlii or of 

 A. grandini. So distmct is it in some fragments (pi. 48, fig. 2) and 

 so similar the union of interfascicular nerves and nervilles to the 

 fascicles that in small fragments it is sometimes necessary to look 

 closely m order to ascertain which is the medial side of the lamina, and 

 which the secondary nerve. On account of the partial maceration of 

 the lamina in the specimens the details of the nervation are not well 

 shown. It is, however, sufiiciently indicated in plate 47, figure 2, and 

 the nature print, plate 48, figure 2, the latter figure in natural size. 

 The sutural nerve in these specimens appears to take the place of the 

 parting between the pinnules of Callipteris. In fact the leaf is not 

 greatly unlike a Callipteris in which the pinnules are completely united 

 and the nerves confluent, in Goniopteris nervation, along the suture 

 except that the veins of each fascicle tend to join the successive nerves 

 of the next fascicle in forming interfascicular nerves which are tribu- 

 tary to the sutural nerves. 



94428°— Proc.N.M.vol.41— 11 32 



