HYDROZOA AND CTENOPHORA. 
Gcel. 3 
20. Guerne, J. de. Meduses d’eau douce et d’eau saum5,tre. Bull. Sci. 
Nord, (2) ii. [1880], pp. 417-424. 
21. Haeckel, E. Metageuesis und Hypogenesis von au7*ito. Ein 
Beitrag zur Entwickelungsgeschichte und zur Teratologio der 
Medusen. Jena : 1881, 4to, 36 pp. 2 pis. 
It appears that under certain conditions the normal developmental 
history may be much shortened, resulting even in the elimination of 
the Scyphistoma- and Strobila-stages. 
22. . Ein neuor Fall von abgokiirzter Entwickelung. Kosmos, v. 
pp. 29-44, 9 woodcuts. 
23. . Badiolarien und Tiefsee-Medusen der Challenger-Expedition, 
SB. nat. Fr. 1881, pp. 67 & 68. 
24. . Mouographie der Medusen. 2 Th. Die Tiefsee-Medusen der 
Challenger-Reise. Der Organismus der Medusen. Jena : 1881, 4to, 
32 pis., 8 woodcuts. 
This is a German edition of the work which appears in English in the 
Report on the Scientific Results of the Yoyage of H.M.S. ‘Challenger’ 
(Zoology, iv., 1882), but which, through some irregularity, was published 
in J ena in the previous year. The report deals partly with the general 
anatomy of the Medusce, partly with the special characters of the eighteen 
species which were diagnosed by the author in 1879 (System der Medu- 
sen : cf. Zool. Rec. xvi. Cod. pp. 8-16), and described as deep-sea forms. 
It must be borne in mind that there is very little evidence that these are 
really deep-sea forms; and, moreover, some of the ‘Challenger’ speci- 
mens wore mere fragments, and the plates relating to these have been 
prepared from specimens in the Copenhagen Museum. The author, how- 
ever, considers that some of them, notably Pcctyllis, Pedis, and Pectan- 
this, among the Craspedotce, and Tesserantha,'Periphylla, Periphema, Nau- 
phanta, and Atolla, point by their primitive structure to a remote 
phylogenetic origin, and so may probably be regarded as permanent and 
characteristic inhabitants of the deep sea. The 18 species represent 13 
of the 32 families of the system. 7 species are reported to have been 
taken in depths from 80-600 fath., 6 species in depths from 1100-1600 
fath., and 6 species in depths from 2000-2200 fath. The author gives a 
complete glossary of the terms used in describing Medusce, in Latin, 
English, and German. 
25. Hamann, Otto. Die Mundarme der Rhizostomen und ihre Anhangs- 
organe. Jen. Z. Nat. xv. pp. 243-285. 
The mouth-arms do not, as is generally supposed, act as suckers. The 
variations in their structure are traced. 
26. Hartog, M. M. On the Means by which Hydra swallows its Prey. 
P. Manch. Soc. xix. pp. 29-40. [Cf. Zool. Rec. xvii. Ccd. p. 4.] 
27. Hertwig, R. Ueber den Bau der Ctenophoren. Jen. Z. Nat. xiv. 
[1880] Suppl. Heft i. pp. 11-16, 29-31. 
The author deals at great length with the minute anatomy of very 
numerous representatives of the group. 
