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f37- Synalpheus trispinosus de Man. 



J. G. DE Man, in: Tijdschr. d. Ned. Dierk. Vereen. (2) Dl. XI, 1910, p. 300. 



Stat. 51. April 19. Madura-bay in the southern part of Molo-Strait. 70 m. Fine grey sand. 

 1 adult ova-bearing female and 1 younger specimen. 



An interesting new species of the Biunguiculatus group characterized, like Syu. triacanthus, 

 by the posterior margin of the 6 th abdominal somite being trispin o se. Frontal region rather 

 prominent, like in some species of the Comatularum group ; rostrum slender, commencing with 

 a rather obtuse carina at the anterior fourth of the carapace and reaching to just beyond the 

 first antennular article, with the acuminate tip curved upward. Immediately posterior to the base 

 of the rostrum one observes, in the median line of the carapace, an oval impressed point. 

 Lateral spines also slender and acuminate, reaching to the middle of the visible part of first 

 antennular article, directed straight forward and upward, so that the tips of these spines are 

 lying in a higher plane than the tip of the rostrum. 



Antennular peduncle 4,5-times longer than wide or thick at the distal end of median 

 article ; the visible part of the first article, the second and the third are in proportion to one 

 another as 16:11:8, the visible part of the first being almost one and a half as long as the 

 second and twice as long as the third ; the second article is almost one and a half as long as 

 wide distall)'. Stylocerite as long as the rostrum, just reaching beyond the end of basal antennular 

 article; the stylocerite and the three frontal spines are setose at their tips. 



Carpocerite 6,5-times longer than wide in the middle, when measured at the lower side, 

 and as long as the antennular peduncle. The lateral spine of the basicerite is slightly turned 

 outward at the tip, clearly shorter than the stylocerite, though almost as long as the basal 

 antennular article; spine at the upper angle well-developed, half as long as the lateral spine. The 

 terminal spine of the scaphocerite is a little longer than the two peduncles and only for a short 

 distance surpasses the tip of the scale, which appears but a little shorter than the antennular peduncle. 



Sixth abdominal somite 1,6-times as wide as long in the middle, the median spine 

 excluded; the posterior margin is armed with three acute spines, the two at the outer 

 angles directed a little outward and a little longer than the spine in the middle. 



Telson a little more than twice as long as the sixth somite, the median spine excluded, 

 2,47-times as long as the posterior margin is wide, proportion between the width at base and 

 that of the posterior margin 1,53. Posterior margin as in Syu. acanthitelsonis Cout., outer 

 angles produced into large triangular spines that just reach beyond the moderately 

 prominent, median part of the margin, spinules on the posterior margin subequal, nearly as 

 long as the spines at the angles. Spinules of the upper surface implanted near the lateral 

 margins, of moderate length, those of the posterior pair 0,35 mm. long, one-ninth the length 

 of the telson, those of the anterior pair 0,3 mm. long; the anterior pair is implanted in front 

 of the middle, the proportion between the length of the telson and the distance of the anterior 

 pair from the posterior margin is indicated by the number 1,78 and the proportion between 

 the distances of either pair from the posterior margin by the number [,7, while the distance 

 between the posterior pair and the posterior margin is just one-third the length of the telson. 



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