M Y S I D E A. 



641 



cephalothorax near base of second and sixth pairs of legs (see figure 

 of E. pellucida). They appear glassy under a lens, as if an eye ; but 

 we have been unable to assure ourselves of the true nature of the 

 organ. 



EtJPHAUSlA PELLUCIDA. 



Gracilis. Carapax brevissime rostratus. Articulus ant&nnarum inter- 

 narum primus apice non productus. Squama basalis antennarum 

 externarum basi paululo longior. Pedes tenuissimi, articido ultimo 

 brevissimo, tribus ultimis simul sumtis precedence fere duplo breviori^ 

 bus, palpo fere triplo breviore quam pes. Segmentum abdaminis 

 ultimwn acutum, lamellis caudalibm paululo longius, barbis subapi- 

 calibus salientibus. Branchiae posticce subdiyitatce. 



Very slender. Carapax very short rostrate. First basal joint of inner 

 antennae not produced at apex. Basal scale of outer antennae a 

 little longer than base. Feet very slender, last joint very short, 

 the last three together nearly twice as short as the preceding joint, 

 palpus about one-third the length of the leg. Last abdominal seg- 

 ment slender acute, slightly longer than caudal lamellae, the two 

 naked subapical setae salient. Posterior branchiae subdigitate. 



Plate 42, fig. 4 a, animal, enlarged; a', same, natural size; b, eye 

 and base of first antennae; c, base of second antennae; c', part of 

 flagellum of same; d, mandible; e, maxillae or maxilliped ; /, maxilla; 

 g, posterior thoracic leg ; h, extremity of abdomen ; i, abdominal leg, 

 with red spherical gland between the two of a pair; k, posterior 

 branchiae; I, ovaries dissected out, partly mutilated, together with 

 two red spherical glands in posterior part of thorax (seen in figure a) ; 

 I', part of same, natural size ; m, m', eggs from the ovary, much more 

 enlarged. 



Pacific, near northern Kingsmill Islands; April, 1841. 



Length, half an inch. Colourless, or nearly so. 



This is a very slender species. The carapax is not higher behind 

 than at middle. The margins of the anterior four abdominal seg- 

 ments are arcuate alike. Eyes nearly orbicular. The inner antennae 



161 



