538 MR JAMES RITCHIE 



Locality, etc. — Burdwood Bank. Lat, 54° 25' S. ; long., 57° 32' W. Depth, 56 

 fathoms. 1st December 1903. 



The occurrence in these specimens of branches sometimes simple and sometimes 

 bearing pinnately arranged branchlets, appears to indicate that this character, upon 

 which Hartlaub founded his S. chilense (1905, p. 671), is rather a variation than a 

 character of specific value. 



Staurotheca, Allman, 1888 (modified). 



Generic Character. Trophosome. — Hydrocaulus fascicled or unfascicled, bearing 

 hydrothecae in longitudinal rows and arranged in a series of transverse planes, each 

 plane containing two or three hydrothecse which exactly alternate with those in the 

 planes above and below them. 



Gonosome. — Gonangia simple capsules springing from the hydrocaulus and destitute 

 of marsupium. 



This genus, as described by Allman, must be slightly modified to include the 

 specimen described below. The alternate arrangement of the successive series of 

 hydrothecse remains constant, but the generic characters must be widened to include 

 not only opposite hydrothecae, but also hydrothecse arranged in whorls of three. 



Staurotheca reticulata, n. sp. (PI. I. figs. 1, 1a, 1b.) 



A portion of a branched hydroid colony 8 cm. in length by 4 cm. in breadth. 

 The stem, which is 0'5 mm. in diameter, is unfascicled, and from it arise, at fairly 

 regular intervals of 5 mm., alternate flexuous branches of the same thickness as the 

 stem, which zigzags between their bases. Smaller branches arise from these main 

 branches and anastomose so frequently, sometimes by means of short, tendril-like 

 processes, that free ends are absent except towards the margin of the colony. In some 

 cases the free ends develop hydrorhizal tubes. All the branches lie in one plane, and 

 this, together with the flabellate form of the colony and the prevalent anastomosis, gives 

 the whole a remarkable net-like appearance, the regularity of the meshwork, at least 

 near the stem, being increased by the fact that the main branches on each side of the 

 stem lie roughly parallel. The internodes are irregular, generally containing about 

 three pairs of hydrothecae in the older branches, while in the younger there is usually 

 a hint of a node between each pair. 



The hydrothecae are placed in longitudinal rows along the stem and branches. In 

 the majority of the branches there are four rows, the hydrothecse being arranged in 

 opposite pairs, which are placed alternately at right angles with one another. Sometimes 

 there are six rows — the hydrothecae in this case being placed in a succession of trans- 

 verse planes, each plane containing three equidistant hydrothecse, which exactly alternate 

 with those in the planes immediately above and below them. The hydrothecse them- 

 selves are cylindrical and deep, with a circular orifice and a smooth margin marked 



