21. The Codiums of the Juan Fernandez Islands. 



WILLIAM ALBERT SETCHELL. 



Willi plates 3 1 — .18. 



The Codiums collected by Professor Dr. Carl Skottsherg in the Juan 

 Fernandez Islands, coming" as they do, from a distinct as well as a remote 

 marine geographic province, necessarih^ raise the question as to what members 

 of this fairly extensive and varied genus have been found either in the islands 

 themselves or on the western coasts of South America. So far as general 

 data of surface temperature is concerned, both Masatierra and Masafuera lie 

 between the isotheres of 15° and 20° C. and between the isocrymes of 10° 

 and 15° C. Undoubtedly there are man}' disturbances of temperature due to 

 currents, both general and local (wind currents particularly) and the usual inter- 

 ference in shallow waters due to greater or less insolation and air temperature 

 influence. There may be expected on the Juan Fernandez coasts, then, a 

 \-ariety of zonal expression, typical of 10 — 20° C. amplitude for outer waters, 

 with tolerance of less regularity or constancy in other temperatures. 



From Juan Fernandez, there seems to have been reported only one 

 Codiuni, ■>•>€. tonieiitosmii-i), collected by H. N. MoSELEY during the visit of 

 the Challenger Expedition. GEORGE DiCKIE, who makes the report (Jour. 

 Linn. Soc, Bot., 15:453, Dec. 1876), adds: — »a slightly branched variety 

 2—3 feet long». The name •i>tojncntosuim^ has, of course, been widely, and 

 often very loosely, applied, almost to each and every either strictly or nearly 

 cylindrical dichotomous Codinin. The note of DiCKIE, however, calls attention 

 to characters which indicate the possibility of this Challenger plant being 

 associated rather with the series of forms clustering around C. decortication 

 (Woodw.) M. A. Howe. Examination of the Challenger specimens (in Herb. 

 Kew!) fully confirms this, and the exact identification will be considered later. 



There are very few references to Codinvi along the west shores of South 

 America. The U. S. Exploring Expedition of 1838 — 1842, under command of 

 Capt. Wilkes, U. S. N., collected one at Valparaiso, Chile, which is recorded 

 (see Bailey and W. H. Harvey, U. S. Exploring Expedition, 17 (Algae): 165, 

 1874) under the »blanket» name of -nCodiuiii adJiaerenSf). SVEDELIUS (in Sv. 

 Exp. till Magellanslanderna, 3, no. 8:299—304, pi. 16, fig. i, pi. 17, fig-s. 

 14 — 19, 1900) lists three (3) species from Tierra del Fuego and West Pata- 

 gonia, under the names: C. nincronatiwi var. californicimi J, Ag., C. contractuni 

 Kjellm., and C. dimorpJiuin Sved. Finally, MARSHALL A. Howe, in his 



39 — 30579. The nat. Hisl. of Juan Fernandez and Easter Id. Vol. II. 



