HYDBOIDA. BALE. 249 



and the dark brown colour. These, however, were overrun 

 by a species of Lafoea, the stolons of which so completely 

 swathed the hydrosoma that no portion of the supplementary 

 tube system of the Cryptolaria was visible except at the 

 extremities of some of the smaller branches. I am indebted 

 to Mr. Briggs for portions of his specimens from Thouin or 

 Wineglass Bay, near Freycinet Peninsula, Tasmania, which 

 being free from the Lafoea, enable me to observe the normal 

 structure. 



These specimens are pale in colour, the dark brown seen in 

 the " Endeavour " specimens residing mainly in the stolons 

 of the Lafoea. In both cases I found a few very young lateral 

 branches, which exhibited the structure before the supplemen- 

 tary tubes had enveloped them. 



A branch at its origin consists of a single slender tube of a 

 length about equal to that of a hydrotheca. On the formation 

 of the first hydrotheca the branch abruptly doubles its width, 

 the hydrotheca being about equal to the axial tube in dia- 

 meter. The hydrotheca is directly in line with the proximal 

 part of the axial tube, which makes a sharp curve round its 

 base. By the time the second hydrotheca is formed fascicu- 

 lation has commenced, two delicate stolons being given off 

 from the base of the first hydrotheca, one on each side, and 

 running along the branch outward. Other tubes originate 

 from the later-formed hydrothecse, and these, together with 

 tubes which proceed from the stern along the branch, make up 

 the fascicle. In the " Endeavour " specimens I observed a 

 couple of very young branches, of two to three hydrothecse, 

 on which the Lafoea had not yet encroached ; these displayed 

 the two first supplementary tubes, but had not developed 

 further, and in none of these specimens could any other portion 

 be found available for observation without hindrance by the 

 Lafoea, which so completely invested the polypary that 

 almost every branch was swathed with it nearly or quite to 

 the extremity, even the latest-formed hydrotheca often 

 supporting a hydrotheca of the Lafoea. Even the gonangia 

 become completely covered by the parasite, which apparently 

 by its close investment, prevents the development of the 

 fascicle-tubes of the Cryptolaria to a great extent. The most 

 advanced La/oea-stolons are generally nearly straight, but on 

 the older portions, and where they have a wider area on which 

 to spread, as on the gonangia, they are most tortuous in their 

 ramifications. 



To Ritchie's account of the hydrothecse I would only add 

 that in some specimens they are continued outward somewhat 



