ZYGOPHYLAX CIIAZALIEI. 15 



and closer relationships, fewer distinct groups, the scientific attitude would 

 seem to look toward the reduction of the number of genera and species, and 

 to limiting the number of new names as much as possible. 



Zygophylax chazaliei Versluys 



Plates 11-13. 

 Perisiphonia chazaliei Versluys. 1 



Two specimens were taken on the " Tangles" at a depth of 300 fms., five 

 miles from the southeast end of Hood Island, Galapagos Archipelago, from 

 a bottom of broken shells and Globigerinae, in Latitude 1° 30.5' South, Lon- 

 gitude 89° 35' West. They are about 40 mm. in height, of a light yellow 

 horn color, and agree very well with the careful description and figures of 

 Versluys. 



Both colonies were broken off short at the bases of the main stems, 

 making it impossible to determine the exact connection of the axial and 

 peripheral tubes with the tubes of the hydrorhiza. The basal portion of 

 the axial tube, when separated from the peripheral tubes, shows a number 

 of peripheral tubes originating from it; all of them are continued upward, 

 some of them branching (PL 13, fig. l). As the thickness of the main 

 stem is determined by the number of peripheral tubes, and as the size is 

 greatest at the base, there must be many peripheral tubes arising from the 

 hydrorhiza ; and as the main stem decreases in size distally, few, if any, of 

 the peripheral tubes from the base reach the top. As pointed out by Vers- 

 luys, the peripheral tubes of the main stem send branches to the pinnae (see 

 PI. 11, fig. o, and PI. 13, fig. :?). The two peripheral tubes between 

 which the hydrothecae project have membranous outgrowths on the portions 

 of their opposed surfaces which lie between the hydrothecae, forming some- 

 thing like a collar around each hydrotheca (PI. 13, fig. tf). 



In some cases there is an internal ring of the perisarc formed close below 

 the hydrotheca (PI. 11, fig. ./,). 



The number of axial tubes at the base of the main stem is about 30, 

 something like 12 of these showing on one half the surface when viewed as 

 an opaque object. This number agrees well with that given by Versluys 

 " pres de son sommet," where, in these specimens, the number is much less. 



1 Memoires Societe Zoologique France, 12, p. 29, 1S99. 



