7S0 
ZOOLOGICAL LITERATURE. 
sp. n., Allni. 1. c. p. 59 j Tubularia humilis, sp. n., Alim., and T. attenuatay 
sp. n., Alim., 1. c. p. 60 j CampanuUna repens, sp. n., Alim. 1. c. p. 61 j 
Syncoryne pulchella, sp. n., Alim. 1. c. p. 465. 
Tubiclava comucopice, sp. u., Norman, 1. c. p. 82, Unst, Shetland j JEudan- 
drium anmdatmn, sp. n., Norman, /. c. p. 83, Burrafirtli, Shetland. 
Haeckel (/. c.) describes at great length the anatomical structures met with 
in the Geryonidae. His work is well illustrated by an atlas of plates, in 
which will be found figured the strange form of reproduction met with in 
this group. 
Haeckel (/. c. p. 85) describes the development of two species of Geryonidae, 
Liriope eurybia and Geryonia hastata. The first is quadruplex, the second 
sextuplex. The sextuple larvae of this latter are probably the result of 
sexual reproduction. But the same species also developes young Medusae 
asexually, and indeed by gemmation, in the interior of the digestive stoma- 
chal cavity, and these have a totally difierent form and structure ; they are, 
moreover, octuple, and are developed in a Medusa, very probably that de- 
scribed by the author as Cimina rhudodactyla. This gemmation, which is 
exceedingly remarkable, both on account of its locality and its heterogeneous 
product, occurs only in the stomachs of sexually mature animals, and in both 
sexes. The singular buds from the tongue of the Geryonia could by no 
metamorphosis be converted into a Geryonia ; if we therefore look for its 
further stages we find it in the free-swimming Cunina rhododactyla, which 
agrees in all particulars with the bud about to be detached from the 
Go'yonia. Should this supposition be confirmed, it requires nolliiug further 
to show that here there is an exceedingly wonderful and a perfectly and 
fundamentally new form of the alternation of generations, or, perhaps better, 
what might be called heterogonism. 
Allman (/. c. p. 468) doubts if Geryonia is a sexual Medusa at all, and 
even believes that the same may be asserted of Cunina. Some years ago he 
insisted on the non-sexuality of those gymnophthalmic Medusse which, like 
Obelia, Encope, &c., cany their generative sacs upon the radiating canals; 
and, pointing out that the structure of these sacs was identical with that of 
the gonosacs of Clava, he showed that they are detinite zooids produced by 
a process of budding from the gastrovascular system of a properly non- 
sexual Medusa. These he called gonoblastocheme,” to distinguish them 
from such proper sexual Medusa as are met with in Sarsia, &c. (gonocheme). 
So in Geryonia, in consequence of the one and the same zooid (the Geryoni- 
dan) producing two sets of heteromorphic buds (the gonosac and the HCgini- 
dan), there is a series presenting two branches, which run off in difierent 
directions. While flaeckel (Allman concludes) has thus done good service 
to our knowledge of the H3Mroida, by pointing out a genetic relation be- 
tween the JEyinidce and the Geryonidce, his labours have been at least as 
valuable in showing that the structure of the AHyinidce is in all essential 
points identical with that of Geryonidce. 
Joshua Alder {1. c.) records a list of fifty-seven species of Hydrozoa found 
on the coasts of Northumberland and Durham. 
'Vetraplaiia voUtans. Krohn’s paper has been mentioned on p. 769. 
