REPORT ON THE CRUSTACEA MACRURA. 509 



The rostrum of this species is slightly turned upwards at the extremity and is armed 

 ou each side with two strong teeth, one near the middle and another at the base, above 

 the inner canthus of the orbit, and there is a third still more posterior ; all stand on an 

 elevated ridge continuous with the lateral margins of the rostrum, and passing back 

 separates the orbital regions from the gastric. 



On the frontal margin, external to and forming the outer angle of the orbit, is a 

 large, obliquely situated, triangular tooth pointing upwards and forwards, and there is 

 another just within the fronto-lateral angle of the carapace where it suddenly turns 

 towards the oral region, producing a prominent fold or process between the first and second 

 pairs of gnathopoda, from the base of which a strong ridge runs backwards and down- 

 wards and unites with the lateral margin just behind the second pair of gnathopoda. 



The visceral regions are well defined on the carapace by a ridge and depression 

 between the gastric and the frontal region ; by a depression between the gastric and 

 cardiac, and by a longitudinal ridge formed of strong cusps between the cardiac and 

 branchial reoions. 



There are five longitudinal ridges that traverse the carapace on each side of the 

 median Une, interrupted only by the lines of regional demarcation. The most lateral in 

 this species is the most continuous; it commences at the fronto-lateral tooth, from which 

 it is divided by the fronto-lateral depression, it then forms two long pointed narrow 

 cusps, and is again interrupted by the latero-branchial depression, after which it is 

 continuous nearly to the posterior margin. The next commences in a strong cusp at the 

 branchio-gastric depression, and is continuous in the form of a long narrow ridge of 

 tubercles to the posterior margin. The next commences in a strong tooth posterior to 

 the orbital region, and is represented by five teeth anterior to the cervical fossa, of which 

 the anterior is the largest and the posterior the smallest, and posterior to the cervical 

 suture is continued in the form of six or seven long narrow cusps to the posterior 

 margin of the carapace. Although this ridge is only definable as such posterior to the 

 cervical suture, yet it is continuous with that formed by the lateral margins of the 

 rostrum ; departing from a straight line it passes inwards to unite with it anteriorly, 

 and posteriorly it breaks up into several strong teeth connected with the ridge that runs 

 to the posterior margin of the carapace. 



The next or dorsal ridge runs one on each side of the median line, and traverses the 

 carapace from the anterior extremity of the gastric region to the posterior margin of the 

 carapace, in the form of a row of sharp narrow cusps, being interrupted only by the 

 cervical suture. AlonL>- the median line of the rostrum there is a small thread-like line of 

 elevation, while the median line as a whole appears to be depressed ; this however is due 

 rather to the absence of tubercles than to an actual lowering of the surface. Between the 

 several ridges the carapace is covered with a number of small, pointed granulations, running 

 in more or less perfect, longitudinal rows. The only portions of the carapace that are free 



