VIII. D, 6 Light: Morphology of Eudendrium 339 



from the typical Eudendrium with its tree-like growth habits. 

 In this particular, E. griffini resembles E. capillar e Alder (All- 

 man, '72) and still more strongly E. parvum Warren ('08). 



Hydranth. — The hydranth is unusually long and slender. Its 

 length, which is very variable, depends on several factors. Some 

 of these factors are sex ; stage of sexual development ; preserving 

 material; and, of course, age. Male hydranths, whether sex- 

 ually mature or not, are long and slender, averaging between 2 

 and 2.5 mm. in length. Among the male hydranths are a few 

 attenuated, sterile hydranths, sometimes as much as 4 mm. 

 in length. In section they show decided signs of degeneration 

 and breaking down of the tissues. The oldest and largest male 

 colony is living on a sponge which has grown up around the 

 hydrocaulus, making it impossible to determine in every case 

 the position of these hydranths on the hydrocauli, but in a 

 number of instances they were found to be the terminal 

 hydranths. Also, a number of terminal pedicels were found 

 which had lost their hydranths. Furthermore, none of these 

 degenerating hydranths were found which 

 could be proved not to be terminal; and, 

 finally, all terminal hydranths found in this 

 colony were sterile and showed some signs 

 of degeneration. In the female colony, as fig. 2. a young colony of 

 in the male, the terminal hydranths are Eudendrium grimm grow- 



ing on a piece of seaweed. 



sterile and the intermediate hydranths are 

 fertile. The sexually mature female hydranths are very greatly 

 shortened and thickened, averaging about 1.2 mm. in length. 

 The terminal hydranths show the same attenuation and breaking 

 down of tissues found in terminal hydranths of the male colony, 

 often dropping off, leaving fragments of their tissues attached to 

 the pedicel. In the female colony, sexually immature hydranths 

 are few and not fully grown. These young fertile hydranths, 

 however, are of much the same proportions as those of the male 

 colony, which would sfeem to show that the type of hydranth found 

 in the normal male may be called normal for the species. All but 

 one of the male colonies are very young with no long hydrocauli 

 and consequently no very old hydranths. Hence, if the atten- 

 uated condition of the terminal hydranths is due to senility, we 

 would expect to find that the terminal hydranths of the young 

 colonies exhibit it much less markedly than those of the older 

 colony, and such is the case. The terminal hydranths of these 

 colonies while longer than the other hydranths are by no means 

 as long as in the older male and female colonies and show no 



