LEPTOSTRACA, SCfflZOPOBA AND STOMATOPODA. 171 



Gonodactylus acanthurus, n. sp. Plate I., figs. 1 L to 15. 



Locality: Muttuvaratu Paar, 45 to 50 fathoms. One female, 10 mlllims. ; one 

 male, 8 millims. 



The rostrum (fig. 11) is of the usual Gonodactylus type, with a long acute median 

 spine reaching very nearly to the cornea of the eye, and slightly produced, hluntly 

 rounded antero-lateral angles. 



The carapace is rectangular in shape, of about equal width throughout. Its 

 antero-lateral and posterolateral angles are rounded. 



The last three thoracic segments have their lateral parts rounded. 



The first lii''' abdominal segments are quite smooth all over, without carinas' or 

 furrows of any kind. The postero-lateral angles of the first four segments are 

 broadly rounded, those of the fifth segment produced somewhat, but rounded at 

 the tip. 



The sixth abdominal segment has the posterolateral angles ending in prominent 

 spines. On its dorsal surface are six carinas, the submedian and intermediate of 

 which are narrowly oval, smooth, and blunt, the lateral ones being somewhat sharper 

 and running into the spines of the postero-lateral angles. The submedian and 

 intermediate carinas do not terminate in spines. 



The telson (fig. 14) has the six marginal spines well developed, long, acute, the 

 laterals slightly curved. There are about nine submedian, two intermediate, and 

 a single lateral, rather long and acute denticles on each side. The dorsal surface 

 of the telson bears three very blunt carinas, the central one broadly oval and larger 

 than the rather narrowly oval lateral ones. The posterior half of the telson, beyond 

 the carinas, is armed with long, powerful, acute spines arranged approximately in two 

 transverse rows, five spines in a row. The first row is placed just posterior to the 

 carinas, and consists of a long median spine immediately below the base of the median 

 carinae, a long intermediate spine immediately behind the lateral carina on each side, 

 and a rather short lateral spine. The second row, which is posterior to the first, 

 consists of five long spines, the median one immediately below that of the first row, 

 the intermediate and lateral ones alternating with those of the first row. There is 

 a moderately long spine on each side of the posterior end of the median carina, and 

 two small median spines. Each lateral carina bears two small spinules at its posterior 

 end and immediately external to the posterior end of these lateral carinas is a small 

 spine. 



The basal joint of the uropods (fig. 15) bears a strong posterior dorsal tooth. The 

 paddle of the endopodite has its inner margin drawn out into six acute spines, its 

 outer margin as usual fringed with setas. The external margin of the basal joint 

 of the exopodite bears eight strong spines. The terminal joint or paddle is small, 

 its inner margin drawn out into three acute spines, its outer margin setose. 



The raptorial claw (fig. 12) is of the usual type, without a notch on the external 

 margin of the dactylus, and the internal margin of the propodus minutely serrated. 



z 2 



