148 
Nia ORE 
[Fune 17, 1886 
more delicate. (d@) A fourth series have their large eggs 
enveloped in dense horny capsules, which either are fixed 
by their twisted filaments to marine bodies or find suffi- 
cient protection on the extensive sandy flats where they 
are deposited. (¢) Finally, a few produce living young, 
this condition ranging from the well-marked ovo-viviparous 
Zoarces to the even more complex state in the sharks. 
It would seem, as far as present observations go, that 
in those fishes which shed their eggs on the bottom, or in 
brood-pouches, the ova are matured simultaneously in the 
ovaries, so that the act of deposition is performed rapidly. 
This is exemplified in the Co/é7,in Agonus (A spidophorus), 
Cyclopterus, Liparis, the herring, and others. In the case 
of fishes with pelagic ova, on the other hand, the ovaries 
mature and shed their contents at intervals, so that the 
process of spawning occupies a period of greater or less 
duration. 
There is little difficulty in the case of the pelagic ova of 
our shores, such as those of the cod, haddock, whiting, 
bib, ling, rockling, gurnard, and others in artificially im- 
pregnating and hatching them, even from fishes that have 
been dead for some hours. The mortality, however, from 
excessive cold and heat is very considerable in a marine 
laboratory, since the limited quantities of sea-water con- 
tained in vessels a foot or even a yard or two across are 
much more subject to such influences than the vast body 
of water in the sea. It has to be borne in mind also that 
the sea-water usually employed in such researches is 
shore-water, and liable to considerable contamination from 
the estuaries of rivers and streams—besides other im- 
purities. The difference, indeed, between such water and 
that of the open sea was illustrated in 1884 (NATURE, vol. 
xxxi. p. 536), when the pelagic ova of the cod could be | 
more successfully hatched in the large glass vessels 
(‘“drop” bottles) in which they were conveyed from the 
fishing-ground without change, than in the ordinary water 
dipped from the shore and frequently renewed. In like 
manner eggs of plaice fertilised on the same ground this 
year (for which I have to thank Capt. Burn, of St. 
Andrews) were conveyed quite safely, even after a week’s 
vicissitudes in a stoneware jar amongst sea-water— lightly 
tied over with ‘‘cheese” cloth. During the late winter 
ova of various kinds suffered severely, however, and the 
effects of such changes of temperature on the embryos 
were even more pronounced. 
The first series of eggs of the haddock were fertilised 
on the 15th, and the second on the 16th of February, but 
the rigorous weather proved ultimately fatal to both. 
The earlier stages proceeded satisfactorily, but the water 
in the vessels by and by was frozen on the surface 
—softish flakes of ice forming a thick coating—on which 
many of the ova were elevated. No sooner was this ice 
broken than all or almost all the ova were observed to 
present the whitish patch and sink to the bottom. 
of those which had floated in mid-water or under the 
trickle from the supply-pipe escaped destruction, but in a 
few days they also succumbed after a night of unusual 
severity, and after the embryos had been outlined. On 
the other hand, a few ova carelessly thrown at the same 
period into a small vessel of sea-water in the window of 
a library escaped injury and developed quickly, though the 
water remained unchanged. 
In the sea the danger from such extreme cold would be 
minimised, since these pelagic eggs in winter and spring 
do not float quite at the surface, but always some distance 
beneath it. 
Under the same circumstances in the laboratory the 
intense frost proved fatal to many adult viviparous blennies 
and Montagu’s suckers, though only the surface of the 
sea-water in the large glass vessels was coated with the 
softish flakes of ice. The fluid in the ovaries of the 
pregnant examples of the former was frozen into a solid 
mass, as was also the liquid in the urinary bladder, yet 
the animals were surrounded in all cases by sea-water. 
Some | 
In the Report to H.M. Trawling Commissioners in 
1884 reference was made to the statement by Alex. 
Agassiz (Proceed. Americ. Acad. of Arts and Sct. xvii. 
p. 289, 1882) that the ova of several species of Cottus 
float. In his recent beautiful memoir along with Whit- 
man (Mem. Mus. Comp. Zool. xiv. part i. 1885), he again 
returns to the subject—giving figures and descriptions of 
the ova of the so-called Cottus grenlandicus, Cuv. and 
Val., which he found in a pelagic condition abundantly 
during the summer months, especially in July. The 
authors, indeed, appear to have met with the ova only op 
the surface of the sea, and do not seem to have identi- 
fied them with those in the ovary of the species indicated, 
which in our country is supposed to be only a variety of 
Cottus scorpius, L. Uniless, therefore, the Cottus graenlan- 
dicus, C.and V., of Prof. Agassiz, is a form very different, 
there is room for doubt in regard to this interpretation of 
its oviposition. 
The spawning of the Cotéz in this country wholly 
diverges. Instead of the issue of the eggs in detachments, 
as in most fishes with pelagic eggs, the ovaries of the 
Cott? become distended at the breeding-season with ripe 
eggs of a uniform size, which are generally deposited in 
amass at once—along with a transparent mucous secre- 
tion. When ejected into the water the eggs adhere to- 
gether, but at first they can hardly be lifted on account of 
the soft and yielding nature of the connecting medium, 
though they do not readily separate. In a few hours the 
| hardening of the connecting medium and the egg-capsules 
stiffen the outer layers of eggs, but the central region is 
still soft. The process of hardening is thus somewhat 
slow, and apparently depends on free contact with sea- 
water. Theseeggsare comparatively largeand thick-walled, 
as well as slow in development, the embryo being ushered 
| into the world in a much more highly organised condi- 
_ tion than in the embryos from pelagic eggs. 
There is, 
indeed, little resemblance between Agassiz’s form and the 
young Cotlus, which is considerably larger, is variegated 
with much pigment, has rudimentary lamellz (papillae) on 
the branchial arches, complex circulatory organs, and a 
small yolk-sac possessing a single large oil-globule ; and 
it shoots upward into the surrounding water like the 
young Lzparis and Cyclopterus. 
While the newly-hatched Coz¢ws therefore greatly sur- 
passes Agassiz’s type in complexity, there are certain 
marine forms, ¢.g. Anzarrhichas, which as greatly surpass 
Cottus. This will be evident when it is mentioned that 
the strongest embryos of the wolf-fish are much more 
highly developed on their escape from the egg than the 
salmon is for a week or two subsequently. Artificial 
stocking of the sea with the valuable food-fishes, such as 
the cod and haddock, would have been comparatively easy 
if their ova and embryos had been as readily handled 
and reared. However, since a noteworthy increase in 
tenacity has been observed in certain forms as soon as 
the yolk-sac has been absorbed, there is room in this 
respect for further investigation. 
THE HONG KONG METEOROLOGICAL 
OBSERVATORY} 
“THIS first-class meteorological observatory was erected 
in 1883, and the regular work of observing began 
on January 1, 1884. Weather Reports appear monthly, 
and we have now before us the observations and work of 
Mr. Doberck and his staff for the first two years. For 
the first two months the work was restricted to eye- 
observations, but meanwhile no time was lost in erect- 
ing the barograph, thermograph, anemograph, pluvio- 
graph, and sunshine recorder, which are similar to those 
in use at Kew; and from April 1, 1884, the Monthly 
¥ «Observations and Researches made at the Hong Kong Observatory in 
the Years 1884 and 1885.” By W. Doberck, Government Astronomer, 
