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146 



STALK-EYED CRUSTACEA. 



from the latter as follows : the rostrum is straighter, its upper surface flatter 

 and smoother, and its lateral teeth (especially the posterior pair) smaller. 

 None of the tubercles of the gastric region are spinous. The orbital spines 

 are not turned so much outward, and the spines at the antero-lateral angles 

 of the carapace are shorter and more robust. There are no spines on the 

 anterior portion of the fourth carina. The eyes are smaller. 



From G, longirostris Smith, it may be distinguished by the rostrum, which 

 in G, sicaria narrows from the anterior lateral teeth, and is not corroded or 

 corrugated on the upper surface ; its lateral teeth, moreover, are not so 

 prominent. The orbital spines are smaller, less deflected outward, and they 

 are separated by a wider interval from the spine at the antero-lateral angle 

 of the carapace. In both species the anterior portion of the fourth carina 

 is divided by a sinus into two prominences : in G. longirostris the anterior of 

 these prominences is the more salient, while, in G. sicaria the posterior one is 

 the more pronounced. 



G. ccecescens W.-M., another similar species, may be distinguished by the 

 lanceolate outline of the rostrum and the presence of two spines on the 

 anterior moiety of the fourth carina of the carapace. 



Family GNATHOPHYLLIDiE. 



GNATHOPHYLLUM Latr. 



I 



Nouv. Diet. d'Hist. Nat., 2« cd., XXX. 72, 1819 [Gnaloph^Uuml 



Gnathophyllum panamense Fax. 



Plate E, 



Bull. Mus. Comp. Zo51., XXIV. 198, 1893. 



This species resembles G. elegans (Risso) of the Mediterranean Sea so 

 closely that I was at first disposed to consider it identical in spite of the 

 remoteness of its habitat. A close comparison^ however, discloses a clear 

 specific difference : in the Panama form a prominent, conical^ obtuse protub- 

 erance, pigmented with black, arises from the upper part of the cornea. In 

 G, elegans this tubercle is wanting or reduced to the merest vestige^ discern- 

 ible only with a strong lens. The rostrum of G, panamense is furnished with 

 seven teeth above, and one below near the tip. The intervals between the 

 superior rostral teeth are furnished wuth long setce. In G. elegans the num- 



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