838 L. A. BOERADAILE. 



and that only one species is known to be closely akin to one from Ceylon is probably due to 

 our very small knowledge of the Hydroid fauna of that island. 



A Campamilaria which was hitherto only known to grow on the back of a turtle has 

 now been found on coral, and a new species was taken on a sea-snake. 



3. As usual, variability has given much trouble from the systematic point of view, 

 making hard to settle both the limits of species in the collection, and also the identity 

 of some of them with forms already described. There is indeed but one of these to which 

 I have applied established names v/hich is not in some way unlike its type. This is, I 

 think, an example of that connection of variation with location to which I have- already 

 called attention in reporting on the crabs of the genus Pilumnus brought home by the 

 exj)edition (11, pp. 195 and 244), and to which I have there restricted the use of the word 

 " subspecies'." Of the presence of " varieties " in the sense in which I have used the word 

 in dealing with the Crustaceans I find no clear evidence among the Hydroids, though I 

 suspect that some, at least, of the forms I have described as new species owe their 

 origin to it. 



4. In the systematic part of the paper I have adopted Schneider's classification (17) 

 with the modifications made in it by Bonnevie (lO), and some small alterations of my own. 

 It will be seen that nine of the forms — about three-eighths of the whole number — show such 

 differences from those already known that they must become new species. All but one of the 

 rest, as I have already said, differ from those nearest to them in ways which do not entitle 

 them to more than subspecific rank. The corbula of Aglaophenia delicatula is described for 

 the first time. 



II. 



The following list sets forth the forms collected by the expedition, with particulars as 

 to their distinguishing characteristics, and notes on other points of interest. 



Order Gymnoblastea. 

 Family Tubularidae. Genus Tuhularia. 



1. Tuhularia pacifica (Thornely) subsp. (16, p. 452). 



The tentacles of the outer ring in my specimens are shorter than in Miss Thornely's, 

 being only about one-third longer than the body when the latter is at full length. The 

 height of the polyp is also less, being only 1 cm. instead of 2 cm. as in Miss Thornely's 

 specimen. 



Dredged in Suvadiva Atoll in 37 fathoms of water. 



Family Eudendriidae. Genus Eudendrium. 



2. Eudendrium maldivense n. sp. (PI. LXIX. fig. 1.) 



Definition : An Eudendrium whose hydrocaulus reaches a height of 4 cm., is not fascicled, 

 and has a fairly stout main stem that sometimes gives off only short, weak, alternate branches 



' As to how far it be due to " vegetative " variation variations by selection, which is, I believe, the cause of origin 

 (13, p. 755) and how far to the piling up of "normal" of subspecies in the Crustacea, there is no evidence. 



