680 CRUSTACEA. 



Length one-eighth of an inch. Colourless. All legs in individual 

 examined imperfect. Abdominal appendages without seise (hence 

 immature), excepting first pair. Caudal lamellae about half as long as 

 caudal segment, and probably not fully developed. First joint of inner 

 antennas as long as other two of base, straight and stout ; the process 

 at lower apex spinulous or serrulate within, branches little longer 

 than preceding joint. 



The last abdominal segment readily distinguishes this species from 

 the microphthalma, the difference being of a kind not obliterated, in all 

 probability, by growth. 



Plate 45, fig. 8 a, 5, represents specimens collected rather abundantly 

 in the Pacific, about three hundred miles southwest of Valparaiso. 

 The last abdominal segment has the same characters, except that 

 it is a little broader posteriorly. The eyes are rather larger than in 

 the above, and the carapax forms a low point between them. The 

 branches of the inner antennae are not longer than preceding joint. 

 The carapax covers all the thoracic legs, and is broader than in the 

 gracilis. 



GENUS CALYPTOPIS, Dana. 



Carapax nan rostratus, oculos tegens. Antennae internee furcatce, articulo 

 primo apice inferiors longd producto. Segmentwn abdominis posticum 

 truncatum apice pectinatum et lateraliter spinulam gerens. 



Carapax not rostrate, covering the eyes. Inner antennae furcate, first 

 joint with the lower apex prolonged acute. Last abdominal seg- 

 ment truncate and pectinate at apex, and laterally bearing a 

 spinule. 



The specimen examined is an immature individual, and may be 

 Macroural or Mysidean. The thoracic legs were but partly deve- 

 loped, and the abdominal were wholly absent. The first antennae 

 and the last abdominal segment resemble these parts in the Furciliae; 

 except that this segment has a spine on the side near its middle. 



