THE MACKEREL MIDGE. 
189 
pany with a few others of allied species at the Kyles of Bute by Mr. Hynd- 
man : they were at the surface of the water.” — -Ann. Nat. Hist. vol. xviii. p. 
315 (1846). 
The following observations on this species were published by me some 
years ago in Annals of Nat. History, vol. ii. 
Description of a minute Fish allied to the Ciliata glauca, Couch , and Gadus 
argenteolus, Mont. Plate XVI. figs. 1, 2, 3. 
When dredging in Strangford Lough, County Down, on the 2nd of July 
last, at from one to three quarters of a mile off the shore, and the water from ten 
to twenty fathoms in depth, 1 for upwards of an hour remarked some very mi- 
nute fishes coming singly to the surface. They ascended in a somewhat verti- 
cal direction, remained but momentarily there, and again, generally in a similar 
manner, descended until lost to view. Their back appeared to be of a dark 
colour, but their sides presented the brilliancy of the brightest silver. Their 
size was rather under an inch ; their motion, though somewhat wriggling, sur- 
prisingly rapid ; so much so, that although the boat was scarcely moving, and 
the sea quite calm, their continuance at the surface was so short, that the great- 
est activity had to be exerted to secure them. For this purpose a small canvass 
net, otherwise used in the capture of minute Medusa , was available. When 
brought into the boat, they at first sight called to mind the Ciliata glauca and 
Gadus argenteolus ; but the great size of the ventral fins, which were likewise 
of a pitchy blackness for nearly the last third of their length, seemed opposed to 
their identity with these species. The boatmen who accompanied me had not 
observed this fish before, nor had they heard anything of it. 
Desc. — General form elongate ; belly protuberant. On a close examination 
of all the specimens, nine in number, no cirri can, with a high power of lens, or 
on the field of the microscope, be detected on either jaw. The largest individual, 
10f lines in length, may be characterized as having the upper jaw the longer ; 
strong and pointed teeth in both jaws ; head occupying rather more than \ of the 
entire length ; eye equal in diameter to |rd the length of the head ; opercle 
rounded at the base, altogether forming a portion of a circle ; first dorsal fin 
originating just over the opercle, so sunken, and its rays (which are thick and 
blunt) so short, as to be hardly distinguishable in the profile of the fish, not less 
than 25 rays ; second dorsal commencing close to the first, and before the end 
of the pectorals, of unequal height, extending to the base of the caudal, not less 
than 50 rays ; pectoral fins rather less than ^th of the entire length, of moderate 
size and rounded, placed very high, somewhat above the opercle, about 20 rays ; 
ventrals placed high, commencing rather in advance of the pectorals, somewhat 
square at the end, occupying \ of the entire length, reaching to the vent, and con- 
sisting of about 6 rays ; anal fin commencing at the vent, and extending to the 
base of the caudal, unequal in height, having at least 40 rays : caudal fin elon- 
gate, occupying ^th of the entire length (measured from last vertebra of body), 
somewhat rounded at the end, containing about 30 rays;* branchial rays about 
7'; vent midway between snout and base of caudal fin. Colour when recent 
— back rich green varied with dots of gold and black ; operculum, entire sides 
and under-surface bright silver ; pectoral, dorsal, anal, and caudal fins uniformly 
of a pale colour ; ventrals likewise so for frds from the base, remainder pitch 
black ; irides silvery. 
Since the above was written, I have been favoured by Mr. Yarrell with original 
specimens of Ciliata glauca , obtained from Mr. Couch, and from these the Strang- 
ford species differs as follows. My specimens, under 11 lines in length, do not, 
like the Cornwall fish — which is 1 inch 5 lines long — exhibit cirri on either jaw. 
The ventral fins in mine are equal to |th of the entire length, in the English spe- 
cimen to about |th ; in the latter the longest rays have a fibrous termination (to 
* Although the number of rays in the fins cannot be given with certainty, an 
approximation to it has been thought better than entire silence on the subject. 
