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strong, flattened, branch iostegal spine or tooth, which is larger than the other 

 spines; this tooth overhangs and even reaches a little beyond the antero-inferior angle of the 

 carapace. Branchiostegal groove, just below the hepatic spine, deep, running horizontally back- 

 ward as far as the upper extremity of the cervical groove. 



First, second and third abdominal terga rounded, the y^ without any trace of 

 a carina; 4* — 6"^ terga strongly carinate, the carinae prominent, that of the 6''^ ending 

 in a distinct tooth. The y^ abdominal somite, 7,5 mm. long, is still longer than the 6"^, that 

 measures 6,5 mm., i.e. about one-third the carapace without the rostrum; the lower margin of 

 the 6* pleura carries a subterminal spinule. The telson which is deeply grooved, is broken off 

 in the middle and the caudal swimmerets are too much injured to be described. 



Eyes smaller than in So/, siphonocera, globular, black, basal joint with a hairy squami- 

 form tooth. 



Antennular peduncle 10,5 mm. long, almost half as long as the carapace, rostrum 

 included; prosarthema not longer than the eyes, stylocerite as long as them, and there is a 

 small spine at the far end of the outer margin of the i^' joint, 2"<i joint twice as long as the 

 3'-<i. Antennular flagella of equal length, the upper (outer) one 23,5 mm. long, as long as the 

 carapace, rostrum included; of the two flagella, that are both abruptly acuminate, the lower 

 (inner) one that slightly narrows distally, is distinctly broader than the other, that shows along 

 its whole length the same width of 0,7 mm.; the lower flagellum, however, 1,2 mm. broad 

 proximally, is 0,7 mm. broad at the distance of i mm. from the extremity. As in the other 

 species of this genus both flagella are compressed, the lower being slightly convex externally, 

 concave internally, whereas the upper is more flattened^). 



Antennal peduncle reaching to the apex of i^' antennular article; the basal joint carries 

 a small spine, directed horizontally forward, at its outer angle, the scaphocerite resembles that 

 of Sol. sipho7iocera and is as much longer than the antennular peduncle as measures the terminal 

 joint of the latter. 



The sternal ridges between the four first pairs of pleopods carry each a sharp conical 



spine in the middle. 



Penaeopsis A. M.-Edw. 

 (MetapeiiaL'us W.-Mas., 1891; Archipenaeopsis Bouv., 1905; Metapenaeopsis Bouv., 1905). 



The genus Pefiaeopsis, established by A. Milne-Edwards in 1881, at present comprises 

 nearly 50 species, the 6 new species of the "Siboga" included. Except three or four, that are 

 inhabitants of the Atlantic, all these species are found in the Indopacific. Penaeopsis serratus 

 A. M.-Edw., the species on which this genus was established, occurs not only in the Caribbean 

 Sea and in the Gulf of Mexico, but is also known from the west coast of Africa, North of 

 the Equator; a variety, antillensis Bouv., occurs in the seas of the Antilles. Pen. megalops 



I) In the older descriptions of the mediterranean Sol. siphonocera, as e.g. in those of H. Milne-Edwards, Heller and even 

 in that of GoURRET (1888), the upper flagellum is described as cylindrical or setiform: this is not right, the upper flagellum, indeed, is 

 as much compressed as the other, not at all cylindrical, but it is much narrower. 



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