[oil MR. JAMES RITCHIE OX HYDHOIDS [May 28, 



II. CALYPTOBLASTEA. 

 Family Haleciid.e. 

 Halecium beaxii Johnston 1838. 



Several strongl^y fascicled, iiregulailj' l:i-anclied colonies. The 

 delicate structui-e of the terminal branchlets i.s characteristic of 

 the species. The branches difler from those in the specimen 

 figured by Allman (1888, pi. xii. fig. 3 a) in arising laterally 

 from below a hydrotheca, instead of directly from the branch. 

 The majority of the primary hydrotheeie diSer f i-om AUman's and 

 from Hincks's (1868) figures in being sessile and adnate to the 

 node from which they arise — the hydrotheca-tier springing from 

 within the primary hydrotheca ; but in these respects they agree 

 with .specimens from the French coast described by Dr. A. Billard 

 (1904, p. 163), and with specimens from dredgings made by the 

 Scottish Antarctic E.xpedition at Burdwood Bank, near Cape 

 Horn (Ritchie, 1907). 



The bright refringent points ^\-hich encircle the base of the 

 hydrotheca are in this species, as in others I have examined (1907, 

 p. 515), points of attachment for strands from a fleshy disc at the 

 ba.se of the pol^-ji, which is thus supported within its minute 

 hyilrotheca. 



The gonosome is absent in the present specimens. 



Localiti/. St. Yincent, Cape Yerde Islands, growing on the 

 bottom of a lighter ; 30th July, 1904. 



OpnioDEs cacixiformis, sp. n. (Plate XXIII. fii^s. 11 i 12 

 Plate XXIY. fig. 1 ; Plate XXV. fig. 5.) 



Several small, delicate colonies, for which this species has 

 been formed, arise at irregular intervals from a hj-drorhizal stolon 

 creeping upon a fragment of a s-md-covered worm-tube. They 

 are neither branched nor fascicled, and the largest is but 6-5 mm. 

 in height. The stem is divided into short interuodes, 0-4 mm. 

 long in the pro.xim.al, liut gradually lengthening to 0-6 mm. in 

 the upper part of the colony. The distal end of each internode 

 appears to divide into two equal, slightly diverging portions, oue 

 of which forms the peduncle of a hydrotheca, while the other bears 

 the succeeding internode, the junction between the two internodes 

 being marked In- a single annulation. 



The hydrothecie lie in one plane, are placed one on each inter- 

 node, and are alternate. The}' are borne on peduncles of varying 

 length, from 0-05 to 0-2 mm., the upper portions of which are 

 delicate and frequently crumpled, while the bases are thick- walled 

 and, even when the hydrotheca itself has been destroyed, remain 

 as projecting processes. The hydrothecaj themselves are shallow, 

 trumpet-shaped cups, with much-everted margins, delicate walls, 

 and a thin septum separating their cavity from that of the stem. 

 Around the wall just within the margin is a row of rafringont 

 points formed bv slight thickenings of the perisarc within the 

 500 



