470 
CCELENTERATA. 
nance, such as the hectocotylus of some Cephalopoda. The ali- 
mentary zooids of the Hydroida he calls hydranths, Huxley ^s 
name of polypite being practically identical with polypide, used 
for the extensile and retractile portion of a polyzoon. The tro- 
phosomes of the N. -American Nemopsis and Acaulis, which have 
been found floating free in the sea, are probably only the detached 
hydranths of fixed forms ; and the statement that Acaulis sub- 
sequently becomes fixed is almost certainly erroneous. The 
Hydroida may be divided into two primary sections : — the Ca- 
lyptoblastic, which possess a gonangium and hydrotheca ; and 
the Gymnoblastic, which (except the freshwater HydrWj form- 
ing a separate section) do not. The entire life-series of the 
Hydroida may be summed up in two fundamental propositions : 
— (1) The fixed plant-like Hydroida give origin to sexual buds, 
both in the form of closed sacs (the sporosac), which develop 
within them the generative elements, and in that of a more spe- 
cialized form of bud, which becomes a free (rarely fixed) Me- 
dusa, ultimately attaining, either directly or indirectly, sexual 
maturity, and producing ova or spermatozoa. (2) The ova of the 
medusiform bud, like those of the sporosac, undergo a continuous 
development, by which they become transformed into hydri- 
form trophosomes, ultimately giving origin, by buds, to Medusa 
identical with those from the ova of which the trophosome was 
directly developed. 
The following species are figured, highly magnified, and accompanied with 
numerous details, chiefly anatomical : — Clava squamata, rmdticornis, and dif- 
fusa, Tubiclava fruticosa and lucerna, Cordylophora lacustris, Corync pusilla 
and vayinata, Syncoryne eximia, pidchella, and frutcscens, Gemellaria implexa, 
Dicoryne conferta, BougainvMlia fruticosa, ramosa, hritannica, and museus, 
Ileterocordylc conyhearii, Terigonimus veslitus, mimdus, and serpens, Bimeria 
vestita, and Garveia nutans. 
Cordylophora laeustiis. F. E. Schulze Uher den Ban und die Entwick- 
lung von Cordylophora lacusti'is, Allman, nebst Bemerkungen iiher Vorkom- 
men und Lebensweise dieses Thieres.’ 4to. Leipzig : 1871, pp. 52, 6 plates) 
has published a very complete monograph, giving its entire structure, ana- 
tomy, distribution, &c. He considers it identical with Tuhidaria cornea, 
Agardh (1810), but prefers retaining Allman’s name, though later. An abs- 
tract is given, Z. ges. Naturw. (2) iv. pp. 490-400. 
Clytia i^Campanularia') voluhilis. The full development of its dilferent 
stages described and roughly figured by G. Du Plessis, Bull. Soc. Vaud. (2) 
xi. pp. 107-170, pi. 2. 
Lovenella, Hincks. The author adds the description of the gonothecae and 
gonozooid to the characters of this genus, and figures and remarks on the de- 
velopment of L. clausa, Loven : Ann. N. H. (4) viii. pp. 79 & 80. 
Coppinin arcta. Structure fully described, and revision of generic characters 
given by Allman, 1. c. pp. 55 & 60. 
Hydra carnea, Ag. On its occurrence in Lake Superior, cf. Smith & 
Verrill, Am. J. Sc. (3) ii. p. 448. 
