CEYLON ALPHEID®. 183 
With regard to the rostrum, [ have found that it shows consider- 
able variation in this species, and consequently I do not consider that 
Coutiére was justified in creating the new variety stylirostris upon 
the form of the rostrum of a single specimen. A careful considera- 
tion of the whole question makes me unwilling to separate any of 
these specimens from de Haan’s species. Coutiére’s knowledge 
of the Alpheide is unsurpassed, and gives him an authority which 
one hesitates to question. But one cannot help feeling that 
many of the characters upon which he has established new species 
appear to be unimportant, and in some cases the material at his 
disposal does not appear to have been sufficiently abundant to 
enable him to say with any justification that these characters are 
constant. 
In establishing his two new varieties, Coutiére makes use of 
certain characters, the chief of which are, (1) the relation between 
the total length of the propodite of the first leg (p) and the length of 
the dactylopodite (d) ; (2) the relation between the height of the 
fingers (/1) and the height of the palm of the first pereiopod (h?) ; 
(3) the relation between the lengths of the first (c') and second parts 
(c?) of the carpopodite of the second pereiopod ; and (4) the relation 
between the length of the triangular rostrum (/) and the base of the 
triangle (5). 
The following table gives Coutiére’s measurements for the three 
species :— 
P Les us y 
d h? c? b 
Synalpheus bis-incisus is, eet hD LG: ET. spout 1-5 
S. bis-incisus, var. malensis .. 2°50 .. 1°34 .. 1°33 .. about 1°5 
S. bis-incisus, var. stylirostris. . Not given 1°53 .. about 3°5 
To illustrate how the Ceylon specimens differ from the above 
measurements I append the following table, giving the characters of 
six specimens belonging to the present collection :— 
Pp h? ch l 
Specimen. d h} eo b 
A PAO ae 1°40 . 1°43 1-83 
B 74a: 3 Nea 1°41 1-51 2°48 
C Bo a. 1°59 1°56 2°72 
D Dis) es 1°36 1°32 2°60 
E Chela absent 1°53 rer iy | 
F 2 BQ e8 1°56 1-60 2°50 
It will be seen that specimen C is the only one which approaches 
A. bis-incisus as diagnosed by Coutiére, except that the rostrum 
is too long. Specimen E appears to be similar to stylirostris. None 
appear to correspond to the variety malensis. 
I have no hesitation in identifying the specimens under discussion 
as Alpheus bis-incisus, and, as I have pointed out, my examination 
indicates a considerable amount of variation in all those characters 
upon which Coutiére formed the new varieties. 
