12 2 



half is slightly curved, as is also visible in the figure of the "Recueil". The posterior half of the 

 carapace is evenly rounded dorsally. The rostrum (fig. 2$ a) is at first somewhat depressed to a little 

 beyond the antennular peduncle and runs from here straight forward, only slisjhtly ascendant, 

 so that the apex is situated at the same level as the curved part of the postrostral crest: 

 in the typical species from Barbados the rostrum is much more upturned and twice as 

 long as the carapace. Uorsall}- the rostrum is armed with 27 — 33 fixed teeth, of which 

 usuall)' the first five, rarely four or six, stand behind the orbital margin; the i^' tooth, which is 

 very small, is placed at '/., — Vio ^^^ length of the carapace from the orbital margin, the following 

 gradually increase in length to about the middle of the proper rostrum, while the remaining 

 teeth that reach to the tij), gradually again diminish in size and therefore appear again more 

 close-set than those in the middle. The lower margin is armed with 22 — 27 teeth, from about 

 the distal extremity of the antennular peduncle to the tip; these teeth are smaller than those 

 of the upper border, close-set and diminish also gradually in size. According to the figure in 

 the "Recueil" in the West-indian typical species the upper border should be armed with 50 to 

 55, the lower with about 70 teeth. 



Orbital spine small, short, not yet reaching the cornea of the eyepeduncles and not 

 buttressed by a carina; branchiostegal spine smaller than the orbital, directed obliquely downward 

 and projecting less forward than the orbital. .\n impressed point or pit exists, at one-third the 

 length of the carapace from its anterior margin, at the level of midway between the orbital 

 and the branchiostegal spine. Branchiocardiac groove slightly indicated, for the rest the 

 carapace is smooth. 



Abdomen little longer than carapace and rostrum combined. On the i*' abdominal tergum 

 are more or less distinct traces of four small tubercles, placed transversely and each of which 

 shows an impressed point, the same tubercles which in some species of the genus Hcterocarpiis 

 are so conspicuous; the two lateral are twice as far distant from one another as the two sub- 

 median ones. Posterior border of ^^^ tergum convex, little prominent. Sixth abdominal somite 

 nearly one and a half to almost twice as long as fifth. Telson almost as long as the 5'^ and 6''' 

 somite combined, sometimes slightly longer than the two preceding somites taken together; it 

 is faintly grooved above and armed w'ith 3 pairs of small dorso-lateral spinules besides those 

 at the tip; sometimes it is as long as the endopoditc of the tail-fan and distinctly shorter than 

 the exopodite, sometimes as long as the exopodite, sometimes even a little shorter than 

 the endopodite. 



Eyestalks of moderate size, cornea large, ocellus quite distinct and almost independent. 



The antennular peduncle does not reach halfway along the antennal scale, namely along 

 -i-M of its length, r' joint as long as 2'"' and 3"' together, 2"'' and 3'''' subequal. Stylocerite 

 flattened, acuminate, reaching to the far end of the 2"'' joint or just beyond it. Antennular 

 flagella subequal, the inner about one-sixth longer than the body. 



Spine at the outer lower angle of the 2'"' joint of antennal peduncle rather short, stout, 

 compre.ssed, acuminate. Antennal peduncle reaching almost to the middle of the 3'"'' joint of 

 antennular peduncle; scale (Fig. i^b) a little longer than two-thirds the length of the carapace, 

 4-times as long as wide, narrowing a little distally, outer margin slightly convex, terminal spine 



