t84 Cs JOURNAL OF SCIENCE. 
Head, and also that the walls should be up to at least high water 
level, and with a distance between them of 500 feet. He evidently 
attaches great importance to the straightening of the entrance, 
and properly so, but as walls to effect that to a satisfactory extent 
would be exceedingly costly, it may be granted that with only 
limited funds at our command, it will be better to attain the 
deepening of the bar first. | 
It is proposed to construct the wall of rubble stone obtained 
from the neighbouring cliffs, and pitch that into the ocean, there 
allowing it to be dressed down to slopes of stability by the action 
of the waves. This system is exceedingly suitable for building on 
sand, and though a certain amount of subsidence will occur, it will 
not be dangerous or costly. This system has been employed for 
the foundations of Cherbourg, Holyhead, Portland, Alderney, 
Boulogne, Madras, and Tynemouth breakwaters, and the Danube 
and Dublin training walls. 
It may be noted by way of comparison, that the widths of 
well-known and much frequented harbours vary from Dover, which 
is 120 feet, to Kingstown, measuring g60 feet. 
The proposal to remove a bar by a concentrated current is no. 
novelty, and has been successfully put in operation in many places. 
Perhaps the case of Dublin is the most convenient to quote at 
present, because it has been very ably and fully described by Mr. 
Mann, the assistant engineer to the Dublin Board. Of the effects 
of the training walls he writes—‘‘ The increase in the depth of the 
channel isremarkable, amounting in some instances to 20 feet, the 
point ot maximum useful effect occurring at about 1500 feet from 
the entrance. The scouring action extends over a large area 
difficult to define, but probably exceeding 800 acres.” And again— 
‘‘ For a distance of about 2500 feet from the harbour entrance the 
average depth below low water has been increased from 11 feet to 
27 feet; for the next 2000 feet the average has been increased from 
6 feet g inches to 18 feet ; and the remaining part of the chan- 
nel to about 6000 feet from the entrance has had its average 
depth increased from 13 feet to 16 feet, so that there is now an 
available depth over the bar otf 29 feet at standard high water, or 
about 28 feet at ordinary springs.” The Otago Bar ought to have 
a corresponding chapter in its history. 
2. **On the structure of the head in Palinuyus, with special re- 
ference to the classification of the genus,” by Prof. T. J. Parker. 
The paper contains detailed descriptions of the head in Palinurus 
edwavdsii, P. vulgaris, and P. imterruptus. As aresult of the examina- 
tion of these and other species, the following phylogenetic table is 
given (see next page). 
The author proposes the following classification of the genus:— 
Genus Falinuvus, Fabr. 
A. Stridulating organ absent ; rostrum well-developed, clasped 
by paired pedate processes of the antennulary sternum ; procepha- 
lic processes present ; coxocerites imperfectly fused ; antennulary 
flagella short. (Sub-genus Fasus, T.J.P.) P. lalandu, P. edwardsn, 
P. hiigellu, P. twmidus. ; 
B. Stridulating organ present; rostrum variable, but rarely (? 
never) as well developed as in section A; pedate clasping pro- 
cesses absent ; procephalic processes absent :— 
(2) Antennary sternum narrow below, bases of antennules be- 
ing hidden—in a view trom above—by bases of antenna ;. 
