REPORT ON 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 : — 



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 (PI. 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 primar}- 

 marginal spines, the intermediates larger than the laterals and having a minute 

 secondary spiuule internal to their bases, and one small secondary .spine between the 

 intermediate and the submedian. The outer margin of the exopodite of the uropod 

 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 has a small 



(ZOOL. CUALL, EXP. — PART XLV. — 1886.) Yy 14 



