I70 



downward and then more or less upward, so that the apex is sometimes placed at a higher 

 level than the postrostral crest, sometimes at the same, sometimes, however, at a lower level. 

 Posterior to the i*' tooth the postrostral crest is not regularly curved, but appears more or less 

 distinctly angular and the angle is usually situated twice as far from the i*' tooth as from the 

 proximal extremity of the crest. Postrostral crest and rostrum armed dorsally with 15 — 19 teeth, 

 usually 16, rarely 12, 14 or 20, ventrally with 10 — 12 teeth, rarely 6 — 9 or 14. First tooth 

 constantly a little ])osterior to the middle, at about two-fifths the length of the carapace 

 from the posterior margin; this tooth is very small, the following become gradually larger to 

 the 5"^ or the 6"^, which is the largest, and then again gradually diminish in size, so that the 

 2 or 3 foremost teeth (also on the lower margin) are rudimentary, almost invisible. Pive 

 teeth stand usually on the carapace, the 6'"' above the orbital margin, rarely four or six are 

 placed on it. 



The rostrum of the full-grown ova-bearing female from Stat. 139 (N" 25 of the Table) 

 shows an abnormal shape and is probably regenerated; 6 teeth stand on the carapace, the 7''' 

 just before the orbital margin. The rostrum, little more than half as long as the carapace, 

 reaches hardly to the end of the antennal scales and projects horizontally forward, the tip 

 hardly upturned. The foremost tooth of the upper margin stands just in the middle of it, while 

 the teeth of the lower are crowded on its distal half, except the first (Fig. 42^). 



P'or the rest as regards form and carination of tlie carapace, this species does not 

 seem to differ from Hete7'oc. ejisifer A. M.-Edw. 



The i^' abdominal tergum (Fig. 42^?) bears a rather high, prominent and very sharp 

 carina that ends posteriorly abruptly, while the anterior margin is sloping and oblique; on 

 each .side of this carina are two small rounded tubercles, of which the superior is situated a little 

 nearer to the carina than to the inferior, and a little below the latter there is a curved ridge, 

 the lower boundary of the tergum. Second abdominal tergum likewise provided with a high, 

 prominent and sharp carina; the straight upper edge of this carina makes usually a 

 right angle with the anterior, but an acute angle with tiie posterior margin of the crest, so 

 that the posterior extremity of the latter appears more or less dentiform ; this is sometimes also 

 the case with the anterior, though the extremities are never sharp. Third and fourth terga also 

 sharply carinate and produced posteriorly into a sharp spine; the two spines are of ecjual 

 length and large, the spine of the 3'''^ tergum reaching to the middle of 

 the 4"^, that of the 4''' to the jjosterior margin of the 5'''; the carina both of the 

 3'''' and of the 4'i^ tergum are slightly curved, that of the 4''' commencing a little beJiind the 

 anterior margin. The 5"^ and the 6* somite like also the telson closely re.semble those of 

 Heteroc. ensifer A. M.-Edw.; the 5''' and the 6"' somite are rounded donsally, the 6''^ one and 

 a half as long as the 5"' or a little less and both somites combined are as long as the telson, 

 which is faintly grooved longitudinally, armed with 4 pairs of dorso-lateral spinules besides those 

 at the tip, and nearly as long as the uropods. 



As regards the two pairs of antennae this species resembles Heteroc. ensifer A. M.-Edw. 

 and this is also the case with the thoracic legs, exce])l lluit the dactyli of the three posterior 

 legs are somewhat longer in proportion to the propodi. 



