ORDER STOMAPODA — MYSIS. 31 



ORDER II. STOMAPODA, 



Shield divided into two parts, the anterior supporting the pedunculated eyes and the antenna. 

 Gills not lodged in thoracic cavities, but exposed and adhering to Jive pair of appendages, 

 sometimes rudimentary or obsolete. The jaw-feet, and most of the feet, which are more 

 than ten in number, approximating to the mouth on two lines converging behind, and 

 giving rise to the name of the order. 



Obs. This order comprises few species, but which differ widely in form. Only a few of 

 these species have been yet observed on our coast. 



GENUS MYSIS. Latreille. 



Body compressed laterally. Six to eight pair of thoracic feet, and furnished with greatly 

 developed palpi, which make them appear double. Mouth placed near the base of the 

 antennas. No thoracic branchiae ; the false abdominal feet very small, and without branchial 

 appendages. 



Obs. The animals of this genus occur in immense multitudes, especially in the northern 

 polar seas. According to Fabricius, they form the principal food of the Whale. 



Mysis spinulosus. 



PLATE VII. FIG. 20. 



Mysis spinulosus. M. Edwards, Hist. Nat. des Crustaces, VoL 2, p. 457. 

 M. id. Godld, Invertebrata of Mass. p. 333. 



Description. Rostrum depressed, triangular, and about one-third of the length of the ocu- 

 lar peduncles. Peduncle of the internal antennas thick and very short ; the lamellar appendix 

 of the outer antennas narrow, and ciliated only within and at the end. Medial caudal plate 

 with spines on its sides, and deeply notched at the end ; the internal plates of the lateral ap- 

 pendices become gradually narrowed towards the end ; the external plates very obtuse (See 

 Desmarest, pi. 40, fig. 6, a.). 



Color, brownish ; each abdominal ring marked above by a black star. 



