[i-rasek] HYDROIDS OF THE VANCOUVER ISLAND REGION 145 



mens of Mquorea forskalea, where the lithocysts are readily seen in the 

 fresh specimens, they have entirely disappeared in less than two weeks. 

 That being the case, many species are put in the genus Thaumantias 

 that should be in the genus Phialidium. The species that Murbach 

 and Shearer described from this coast as Thaumantias cellularia 

 Haeckel 21 , certainly has numerous lithocysts and apparently no real 

 Thaumantias has been collected from this coast. Mayer in his Mono- 

 graph, includes Thaumantias inconspicua Forbes with Phialidium 

 hemisphericum, 22 and during the summer of 1912 evidence was ob- 

 tained at the Departure Bay Station that corroborated this conclusion. 



Calkins found some specimens of what he called Campanularia 

 inconspicua in Puget Sound and later I found similar species in San 

 Juan material and reported it as Thaumantias inconspicua, as there 

 seemed little doubt that it was the same species in which Wright reared 

 the hydroid from the medusa. Dr. McMurrich, while working on the 

 medusae of this region, successfully reared some hydroids from the 

 eggs of Phialidium hemisphericum and these hydroids were not dis- 

 tinguishable from the hydroids I had referred to Thaumantias in- 

 conspicua. I have shown a figure of one of these reared hydroids that 

 it may be compared with that of some specimens obtained from 

 Banks Island. 



The difficulty now is to know what the species should be called. 

 Mayer says that the Clytia medusae are distinguished from the Phiali- 

 dium medusae, in that they have the same number of lithocysts as 

 tentacles, arranged alternately, while the latter have a greater number 

 of lithocysts than tentacles and these are not regularly arranged. 

 Since these medusae are still in the four-tentacle stage when they are 

 liberated from the gonangium, it would be a very difficult matter to 

 make a classification that would effect the hydroid on that basis. As 

 a matter of fact, that has not been done as every hydroid that produces 

 medusae that would answer to the description of either of these at the 

 four-tentacled stage has been classified as a Clytia, and it is quite prob- 

 able that many of the hydroids that are now called Clytia produce 

 Phialidium medusae. In fact, Dr. McMurrich found it impossible to 

 distinguish the young stages of the medusae of Phialidium hemisphericum 

 from the medusae that I obtained from the hydroid Clytia edwardsi. 

 It seems best, therefore, to place the species in the genus Clytia. 



But the difficulty does not end here. If the medusa Thaumantias 

 inconspicua is the same as Phialidium hemisphericum, the name 

 "hemisphericum" dates back to 1760 and it was not until 1848 that 

 Forbes used the name ''inconspicua." It was the latter name, how- 



21 Proc. Zool. Soc. London, vol. 2, 1903, p. 172. 



22 Medusae of the World, vol. 2, 1910, p. 266. 



