414 
ness of the skin in glands, the structure of the hyoid bone, 
the double occipital condyle of the skull, the rudimentary 
ribs, the branchiae in the young. Lachrymal glands are en- 
tirely absent in fish, but present in Coeciliae. The “ false 
nostril ” is either homologous with the cephalic fossa of 
Ophidians or is a special organ. 
Embryology. — Researches on the Development of the Chce- 
topoda. By Edouard Claparede and Elias Meczniknow. Kol- 
liker's und Si eb old's Zeitschrift, vol. xix, prt. 2. — During 
a residence at Naples in the winter of 1866-67, the two dis- 
tinguished observers whose valuable paper we have before 
us, had an opportunity of studying the development of many 
species of Annelids, and of filling up some of the many 
lacunae by which this subject is as yet marked. The method 
of their researches was various, although not new. By means 
of the towing-net many larvae were obtained and watched for 
various periods in their development. Masses of the ova, toge- 
ther with the mother-worm, were also in some cases obtained 
and hatched in vessels, whilst some species deposited their 
ova which developed in the aquaria which the observers kept. 
The authors do not consider all the larvae which they observed 
as worthy of further notice ; they have confined their illus- 
trations, comprised in six coloured folding plates, to those of 
which they could determine the species, or at any rate the 
genus, with certainty. As a general result it appears that 
the division of Annelid-larvae into several groups — such as 
has been essayed by Busch, Joh. Muller, and Claparede him- 
self — has but a very subordinate importance. The names 
Atrochae, Telotrochae, Polytrochae, Mesotrochae, Nototrochae, 
Gastrotrochae, &c., indicate only transitory conditions, and if 
adopted we should have often to group the larvae and the 
adults in incongruous assemblages. Thus many Terebella- 
larvse are true Nototrochae, others develop bands and circles 
of cilia ; whilst many larvae of Eunicidae are really Polytrochae, 
others, on the contrary, are Atrochae in Muller’s sense. This 
dissimilarity in the larvae of very closely allied Annelids 
should excite no surprise, since the development of bands of 
cilia, or of continuous ciliated tracts for locomotive purposes 
in these early stages must depend on the free or confined 
nature of the life to which the larva is to submit during 
development. Thus the Terebella-larvae of pelagic habit are 
regular Nototrochae, whilst the larvae of other Terebellae 
never go far from the egg mass, and the ciliated tracts are 
proportionately deficient: according to hitherto received prin- 
ciples these various Terebella-larvae would be classed in very 
