124 Alexander W. Evans, 



appressed papillae and the wings three cells thick which are char- 

 acteristic of the older species ; and the male branches present, 

 which Stephani does not mention in his description, are likewise 

 unmistakable. 



3. Riccardia Savatieri (Steph.) comb. nov. 

 Aneura Savatieri Steph. Hedwigia 32: 26. 1893. 



Specimens examined: York Bay, Straits of Magellan, Lechler 

 (M.) ; Grappler Bay, Straits of Magellan, 1893 A. E. Douglas 

 (H., Y.) ; Rio Azopardo, Tierra del Fuego, 1896, Dusen /d (N. 

 Y., as Aneura Savatieri, apparently listed by Stephani as A. pre- 

 hensilis, see 29, p. 9). 



The following records for R. prchensilis, cited by Bescherelle 

 and Massalongo (2, p. 244), should probably be transferred to R. 

 Savatieri: ]\Iere-le Dieu, Wellington, Clarence and Hoste Islands, 

 Otway Bay and Isthmus Bay, Savatier. 



In general habit and color R. Savatieri resembles R. prehensilis 

 in a marked degree. The prostrate axis is even more rigid and 

 robust, however, and attains a length of 5-10 cm., or even of 15 

 cm. according to Stephani's description. This axis, which exhibits a 

 long-continued growth, is flattened and distinctly winged through- 

 out its entire length. It shows a width of 0.9- i.i mm. and a thick- 

 ness of 0.3-0.4 mm. in the median portion. Its structure is much 

 the same as in R. prehensilis. In the median portion, where it is 

 about twenty cells thick (Fig. i, G), it shows a flattened central 

 strand of elongated cells. The interior cells of the strand have thin 

 and unpigmented walls but an exterior zone, one to three cells thick, 

 is composed of cells with thickened and usually pigmented walls, 

 the color varying from yellow to light or dark brown. Outside 

 this zone there are usually two layers of short cells or, in places, 

 three layers. The cells of the superficial layer show thickenings at 

 their angles in surface-view and project very slightly as rounded 

 papillae (see Fig. i, I). Their walls are otherwise only vaguely 

 thickened and the same thing is true of the cells between this layer 

 and the thick-walled zone of the central strand. In spite of their 

 differentiation the cells do not vary greatly in size, when seen in 

 cross section, the average diameter being about 20 jx, but the sur- 

 face-cells are often 25-30 ju, wide. On the sides the axis thins out 



