CRUSTACEA CASPIA. 439 



The inferior antennae (ibid.) exceed half the length of the superior, hut 

 otherwise agree in structure with those in the preceding species. 



The gnathopoda, which however in the solitary specimen could not be 

 examined more closely, appear somewhat less unequal than in G. tuberculafa, 

 though apparently of a very similar structure. 



In the structure of the pereiopoda and uropoda, no essential difference 

 from that found in the preceding species, could be detected. 



The telson (tig. 23), on the other hand, looks very different. It is of a 

 triangular form, being about as long as it is broad at the base, and has its 

 outer part conically tapered. The cleft is very narrow and confined to only 

 the outer half of the telson. The lateral lobes are pointed, and each armed 

 at the tip with a minute spine accompanied by 2 small hairs. 



Occurrence. — The above-described specimen was taken by Dr. Grimm 

 in the southern part of the Caspian Sea, from the considerable depth of 108 

 fathoms. 



Gen. Gammaracanthus, Sp. Bate. 

 8. Gammaracanthus caspius, Grimm. MS. 



(PI. 4, figs. 1—6). 



Specific Characters. — Dorsal carina distinct throughout, the anterior 

 segments of the mesosome also being elevated to well-detined lamellar ex- 

 pansions, that of 1 st segment rounded, the others triangular and successively 

 increasing in size, those of metasome and urosome sharply pointed. Rostrum 

 but very slightly curved, and extending to the end of the basal joint of the 

 superior antennae. Coxal plates nearly as in G. relictus; epimeral plates of 

 metasome acutely produced at the lateral corners. Eyes oval reniform, with 

 a well-marked sinus anteriorly. Antennaj nearly as in G. relictus. Anterior 

 gnathopoda with the propodos scarcely as large as that of the posterior ones, 

 and much less elongated than in G. relictus. Pereiopoda comparatively less 

 slender than in that species, outer part of the 3 posterior pairs densely 

 clothed with short spines. Uropoda and telson of the usual structure. Length 

 of adult female 36 mm. 



Remarks. — The present form is nearly allied to G. relictus G. 0. Sars, 

 but exhibits some well-marked differences, so as more properly to be regarded 

 as a distinct species. Both forms, however, are in all probability originally 

 descended from the arctic species, G.loricatus (Sabine); indeed, the present 

 species exhibits in some points a closer relationship to that form than 

 does G. relictus. 



Description. — Tlie length of the largest specimen examined, an adult, 

 ovigerous female, measures no less than 86 mm., and this form accordingly 



*H3.-MaT. CTp. 269. 19 30* 



