57 



considers to be the taaiiatus of Lamarck, and the correctness of this identification is shown by 

 the fact that by Lamarck himself Palin. versicolor was regarded as a synonym of his Pa/in. 

 taeniatus (Histoire nat. des animaux sans vertèbres, 2 e Edition, T. V, p. 372). 



Panul. versicolor (Latr.) and Panul. ornatus (Fabr.) are, 110 doubt, different species 

 and may be distinguished by the following characters: 

 i° by the quite different and characteristic coloration. 

 2" by the exopodite of the maxillipeds of the 2 nd or penultimate pair, which in Panul. ornatus 



bears no flagellum at all, while in Panul. versicolor it carries a distinct, though small, 



rudimentary and inarticulate flagellum. 

 3 by the terga of the abdominal somites, which in Panul. ornatus are constantly smooth, 



while in Panul. versicolor interrupted transverse furrows are observed on the 2 nd to 4" 1 



segment in specimens of a certain age. 

 4 by the somewhat stouter shape of the external maxillipeds and of the legs in Panul. ornatus. 

 There are, however, probably still other differences. In both species one observes on 

 the cardiac region, on either side of the middle line, a longitudinal rovv of 3 spines: in Pantel, 

 ornatus the two rows distinctly converge backward, while in Panul. versicolor they run parallel. 

 There are, in both species, on either side of the supra-orbital spines, two spines, one at the 

 lateral angle of the carapace, the other between this spine and the supra-orbital one. This 

 second spine now appears in Panul. ornatus distinctly smaller than the lateral spine and 

 than the spine which is situated immediately behind the supra-orbital one, in Panul. versicolor, 

 however, the second spine is not smaller than the two others and directed outward, in Panul. 

 ornatus, on the contrary, straightly forward; this second spine is, moreover, in Panul. ornatus 

 situated a little farther dis tan t from the anterior margin of the carapace than in the other 

 species. The spine at the antero-lateral angle of the carapace has the tip slightly directed outward 

 in Panul. versicolor, slightly inward in Panul. ornatus. The pleura of the abdominal somites, 

 finally, are more acuminate in Panul. versicolor than in Panul. ornatus. The last mentioned 

 differences were observed by me after having compared the adult male specimens of Panul. versi- 

 color, obtained by Mr. Jacobson, with the adult male of Panul. ornatus (Fabr.) from Stat. 7 1 . 



Of the largest male from Sinabang-Bay (Simalur) the carapace measures 91 mm., the 

 telson 57 mm. r ) and this specimen almost fully agrees with Gruvel's figure 3 of his sixth 

 Plate, also as regards the coloration, even in minute details, the only differences being shown 

 by the antennular peduncles and by the legs which are slightly longer with regard to the peduncles 

 of the external antennae. The 2 nd joint of the antennular peduncle in this specimen just reaches 

 beyond the tip of the peduncle of the outer antennae; the legs of the i 4t pair reach almost 

 this tip, while those of the 3 rd extend by a little more than the dactyli beyond it, the legs of 

 the 5" 1 pair attain the distal end of the penultimate joint. This difference, however, is only 

 apparent, for it is easily explained by the position of Gruvkl's specimen, when it was photo- 

 graphed. In this male the ischium-joint of the external maxillipeds (PI. II, hg. 7^) appears, when 

 measured in the middle of the outer surface, i^Lmm. long and 10 mm. broad, the merus-joint 



1) The length of the abdomen coukl not be measured with certainty, because it was bent inward and because it could not 

 be stretched out. 



SIBOGA-EXPEDITIE XXXIX a-, S 



