390 Rev. T. Hincks on the History of the Hydroida. 



occasionally opposite towards the base of the plume, simple, 

 moderately distant, a single calycle on the main stem at their 

 origin. Hydrotheae cup-shaped, deep, with an even margin, 

 separated by two joints. SarcotJiecm bithalamic, one on each 

 side of the calycle above and one below it, two on the inter- 

 mediate internodes of the stem and one on those of the pinnae, 

 and two on the longer internode near their base. Gonothecce 

 shortly pedunculate, sj)ringing singly or in pairs from the base 

 of the calycles both on the stem and pinnas : female in the 

 shape of an inverted horn, curved inwards towards the calycle ; 

 aperture suboval, oblique ; two sarcothecEe near the base : male 

 unknown. 



Height of plumes about | inch. 



Hah. On stones, dredged off the Capstone at Ilfracombe. 



The plumes of P. cornu-copue are compact and slightly re- 

 curved. The pinnae are not very distant, and of moderate 

 length, seldom bearing more than six calycles; I have never seen 

 them branched. The internodes which separate the hydrothecae 

 are not nearly so long as in P. Catharina^ and bear only one 

 sarcotheca, whereas there are two or three in the latter species. 

 The much greater length of the internodes, both on the stem 

 and branches, in P. Catharina confers on this species a very 

 distinctive habit. It approaches P. cornu-copice in many of 

 the details of its structure, but not at all in general appearance. 

 The pinnae of the latter species are decidedly alternate, with 

 the exception I have mentioned above. The most striking 

 feature undoubtedly is to be found in the gonothecse, the pecu- 

 liar form of which has suggested the specific name*. They 

 originate, as in P. Catharina, at the base of the calycles, 

 sometimes singly, but frequently in pairs, and are perfectly 

 hyaline and of the most delicate texture ; they are of ample 

 size and most gracefully curved, bearing, like the similar parts 

 in the allied species, two of the bithalamic sarcothecae near 

 the base. The polypites are adorned, just below the tentacles, 

 with a conspicuous belt of opaque white, which forms a striking 

 feature. 



III. Reproduction hy Fission in Campanularia neglecta, 



Alder. 



[Plate XX. fig. 4.] 



Allman has described a case of reproduction by spontaneous 



fission in a Campanularian Hydroid which he has referred to 



a new genus under the name of Schizocladium^. I have had 



* Tlie gonotheca is like an exquisite little crystal cornucopia. 

 t Report of the British Association for the Advancement of Science, 

 1870 ; ' Monograph of the Gymnoblastic Hydroids,' part i. p. 151. 



