64 Miscellaneous. 



tem. Their stomachal peduncle, according to him, is destitute of 

 gastrovascular canals, and represents a tube, hollow throughout and 

 filled with chyme, communicating directly with the radiating canals 

 of the umbrella. Hackel proves that this character is erroneous. 

 The peduncle in the Geryonidae, as in the Geryonopsidae, is solid 

 and hyaline, the stomach occupying only its lower or buccal extre- 

 mity. From this stomach issue the gastrovascular canals, which are 

 excavated in the peripheral layer of the hyaline peduncle, and run 

 towards the umbrella. M. Hackel remarks that the Geryonidae 

 form two very natural groups, according as they are quadruply or 

 sextuply rayed ; and he therefore forms with them two subfamilies, 

 that of the Carmarinides and that of the Liriopides. The Carma- 

 rinides, with sextuple rays, are distinguished by their large size, not 

 only from the Liriopides, but also from nearly all the other Craspe- 

 dote Medusae ; so that they may be regarded as giants among these 

 Hydrozoa. 



A very singular organ which occurs in certain Geryonidae of both 

 subfamilies, is a solid, gelatinous, hyaline cone, which springs from 

 the bottom of the stomach, and, traversing its whole cavity, projects 

 through the mouth. This organ, called by the author the " lingual 

 cone," appears to be endowed with tactile functions ; but it is also 

 intimately connected with those of reproduction. Its existence was 

 previously known in the four-rayed genus Liriope ; but the author 

 has also found it in the new six-rayed genus Carmarina from the 

 Mediterranean. 



Certain Carmarinides present a modification of the gastrovascular 

 system which is unique in its kind among the Craspedote Medusae. 

 "We find in them, besides the normal radiating canals, centripetal 

 canals which start from the marginal canal and are directed towards 

 the base of the stomachal peduncle, where they terminate caecally. 



The Geryonidae appear to be furnished with a nervous system, the 

 principal part of which presents the form of an annular cord, placed 

 immediately beneath the marginal canal, and bearing ganglionic in- 

 flations at the positions of the marginal corpuscles. Here, therefore, 

 we have a new champion in support of the controverted existence of 

 a nervous system in the Medusae. But it is as well to remark that 

 the nervous system described by Hackel appears to be essentially 

 different from that indicated by iVgassiz ; it is also distinct from the 

 organs regarded as nervous by F. Miiller m Liriope, and only appears 

 to coincide with the nervous system observed by F. Miiller iwTamoya, 

 and by Leuckart in Eucope. 



The tentacles of the adult Geryonidae are at least as numerous as 

 the radiating canals, and are then placed at the extremities of the 

 latter. There are consequently at least four of them in the Lirio- 

 pides, and six in the Carmarinides. But many species also possess 

 interradial tentacles, which appear, likewise, to exist in all the species 

 when young. Moreover, during a certain period of larval life, all the 

 Geryonidae appear to possess supplementary or accessory tentacles, 

 inserted upon the dorsal part of the umbrella, a little above the radial 

 tentacles and upon the same meridians as these. During this period 



