[CEYLON PEARL OYSTER FISHERIES 1904 SUPPLEMENTARY REPORTS, No. VIII.] 



REPORT 



ON THE 



HYDROIDA 



COLLECTED BY 



Professor HERDMAN, at CEYLON, in 1902. 



BY 

 LAURA R, THORNELY. 



[With PLATES I. to III. and TEXT-FIGURES.] 



INTRODUCTORY. 



This collection of Hydroids from Ceylon comprises 43 species, of which 13 are now 

 described as new to science, and one of these requires the formation of a new genus. 

 A few specimens are too small in quantity to have more than a generic name assigned 

 to them. 



Our knowledge of the Hydroid fauna of Indian seas* is mainly due to Armstrong, 

 who described a few species from the Bay of Bengal, two of which are represented 

 in our series ; to Allman, who worked out a small collection sent home by 

 Mr. Holdsworth from Ceylon in 1874, containing two of our most striking species; 

 and to Hincks, who described a small collection made by Dr. John Anderson in the 

 Mergui Archipelago in 1889, two species of which we have. 



But the faunas of Australia and the East Indies are evidently similar in many of 

 their species, and we have several of those described by Bale and von Lendenfeld. 

 It is also clear that some of our species have a wide distribution over the globe, as 

 we find in our Ceylon list Plumularia setacea and Cuspidella costata, both British 

 species, and the former recorded from North America, Australia, and New Zealand, 

 while the latter has been found in North America. 



* See List of Literature, p. 125. 

 P 2 



