AGALMIDAE. 273 



The form of the tentilla is much more precise. The primary tentacle 

 of all Agalmids in which it is known, bears tentilla quite different from those 

 of the later formed cormidia. They are usually only transitory, in fact the 

 oldest siphon is usually dropped bodily. But in one species all the tentacles 

 have tentilla of the primitive type. This species is the only representative of 

 the genus Anthemodes. In all other Agalmids the definitive tentilla have either 

 one terminal filament, two filaments and a median ampulla, or many filaments 

 with an ampulla; in other words they are eithei- unicornuate, tricornuate, or 

 polycornuate. The latter condition characterizes one species alone, Agal- 

 mopsis utricular ia Claus {Lychnagalma vesicularia Haeckel). This species 

 is not included in Chun's ( '97b) list : l)ut the description and figures of it are 

 detailed, and show that it is a very well-defined form. 



In the development of the individual tentilla, so far as is known, the rudi- 

 ments for the full number of filaments, and the ampulla if present are formed 

 simultaneously at a very early stage. They are not added successively. Later 

 on, the involucre develops in those species in which it occurs. It is evident 

 that we can speak of successive degrees of specialization of the tentilla, something 

 we cannot do in connection with the general "habitus"; and a character show- 

 ing degrees of specialization is eminently fit to serve as the basis foi' classifica- 

 tion. Now, in the two groups with unicornuate and with tricornuate tentilla, 

 other minor characters, e. g., foi-m of the bracts, distinguish several species; 

 and therefore it is entirely justifiable to follow Bedot ('9(i) in using the 

 structure of the tentilla as the chief generic character. 



On this basis, two genera, Anthemodes with tentilla of the primitive type, 

 and Ljehnagalma in which the tentilla have a whorl of eight (or more?) terminal 

 filaments and a very large median ampulla, may be accepted without further 

 discussion. The only Anthemodes yet known is .4. ordinata Haeckel (A. moseri 

 Agassiz and Mayer has unicornuate tentilla and is a synonym of Ste-phanomia 

 (Cupulita) bijuga Delle Chiaje). Lychnagalma vesicularia Haeckel ('88b) the 

 type of its genus was later shown to be a synonym of Agalmopsia ulricularia 

 Claus ('79). 



Neither of these genera is represented in the "Albatross" collection. 



The remaining species of Agalmidae are divided by Bedot into six genera, 

 Agalma, Crystallomia, Stephanopsis, and Agalmopsis with tricornuate; Hali- 

 stemma and Cupulita with unicornuate tentilla. The members of the first 

 group are separated by such minoi' characters that I have no hesitation in uniting 

 them. Thus the supposed hydroecial cavity of Agalma is probably accidental. 



