PEPOPT OH THE STOMATOPODA. 
105 
a few larval formss elected from the numerous Challenger specimens which I refer to this 
genus, or to the subgenus Coronis. 
Coronis (. Erichthus ) minutus. — From a collection of larvae taken in the tow-net at St. 
Vincent I have selected the series which is shown in PI. XII. fig. 4 ; PI. XIII. 
figs. 1-8, and 11, all of which undoubtedly belong to a single species. This is shown 
by their general resemblance and also by the accompanying table of measure- 
ments. The length of the four specimens, measured from the tip of the rostrum 
to the tip of the telson, are as follows : — 
If the length of Ho. 1, which is 446 mm. 
he successively multiplied by f, we shall 
Ho. 1. 
446 mm. 
Ho. 2. 
5 - 29 mm. 
Ho. 3. 
6 '49 mm. 
Ho. 4. 
10'21 mm. 
have the following series of numbers, 
446 
5-20 
6-50 
843 
1046 
and the close agreement between the measured and the computed length shows that 
Nos. 1, 2, and 3, are successive stages, and that there is a stage which is not represented 
in the collection between Nos. 3 and 4, and that the length of the larva increases 
uniformly at each moult by one-fourth of its length before the moult. It is hardly 
conceivable that an accidental collection of unrelated specimens should show such close 
conformity to a numerical law, and we may safely decide that the larva shown in PI. XII. 
fig. 4 becomes transformed, through the stages described, into the one shown in PI. XIII. 
fig. 7. This latter larva is so similar to the larva of Lysiosquilla ( Coronis ) excavatrix 
that the series from St. Vincent may also be safely referred to an adult of the subgenus 
Coronis of the genus Lysiosquilla. It does not seem to have been described, and on 
account of its small size, I propose for it the provisional name Erichthus ( Coronis ) 
minutus. 
The diagnostic characteristics of this species are as follows : — A small Erichthus 
with a broad flat hind body, a rostrum less than half as long as the carapace, and with 
the postero-lateral spines of the carapace ventral, and without a tooth ventral to their base ; 
the raptorial claw (PL XIII. fig. 11) is flat and oval, and there is one large spine on 
the anterior edge of the carpus close to its proximal end. The telson has six primary 
marginal spines, the intermediates larger than the laterals and having a minute 
secondary spinule internal to their bases, and one small secondary spine between the 
intermediate and the submedian. The outer margin of the exopodite of the uropocl 
has few spines, and the basal prolongation ends in a long slender acute outer spine 
with a broad base, and a very small inner spine. The carapace with the rostrum makes 
a little more than half the total length, and its posterior edge, which lias a small 
(ZOOL. CHALL, EXP. PART XLV. 1886.) Yy 14 
