34 Explanation of the Plates illustrative of 



MYSIS. 



Plate iri.Fig. 1. Side view of Mysis vulgaris magnified ; the straight line 

 near it expressing its real length when fully grown. 1 a, innermost seta of 

 the right superior antenna. 2 a, its outermost seta. 3 a, setae of the inferior 

 antennae, s, anterior scales, e, eye. p, palpi. 1 /, prehensile, or innermost 

 rows of feet. 2/, natatory or exterior feet. 3/, sub-abdominal fins, m, 

 valvular sub-pectoral pouch, or receptacle of the young in the female, c, the 

 cephalo-thoracic-clypeus. The five-jointed posterior part of the trunk, and 

 the tail require no figures to make them obvious. 



Fig. 2. The anterior part of the animal from above, more highly magni- 

 fied, shewing the taper pointed form of the anterior Scales, the form and 

 position of the superior antennae, with regard to the inferior and exterior 

 pair, the pointed termination of the Clypeus in front, and the Eyes. 



Fig. 3. The Tail from above, magnified in the same degree with fig. 2, for 

 the purpose of shewing the form of the lamina?, and particularly the middle 

 one, with its spinulose margin. 



Fig. 4. One of the Palpi from within, very highly magnified, a, basil 

 joint, by which it is articulated to the mandible, b middle joint, c last joint, 

 ending in a strong spine and a row of muricated clavae, and having'a.row 

 of hooks along one margin, and a double decussating row of bristles along 

 the other ; to do justice to the curious and complicated structure of^this one 

 joint it would require the entire plate to itself. 



Fig. 5. The basis of one of the superior antennae in the male, to show its 

 brush-like appendage ; the setae have been cut off short ; x indicates the 

 point of attachment to the animal. 



Fig. 6. One of the first pair of feet, (the left) highly ;;magnified, x point 

 of attachment, a its inner division, b its outer division abbreviated, as being 

 similar to those of all the other feet, g its brauchia. 



Fig. 7. One of the second pair of feet, (the left) highly magnified, x point 

 of attachment. The same letters indicate the analogous parts in fig. 6, 7, 

 and 8. In this figure, the outer or natatory division of the limb is fully 

 represented. 



Fig. 8. One of the last (or of the eighth) pair of feet, (the left) highly magni- 

 fied ; shewing the pluri-articulate tarsus of the inner division, consisting of 

 about ten joints, and ending in a short claw. The 3d, 4th, 5th, 6ih, and 7th 

 pair of feet are exactly similar. Fig. 12, shews the tarsus and claw, as they 

 appear when the young animal first emerges from the maternal pouch. 



Fig. 9. One of the sub-abdominal natatory fins, very highly magnified, 

 consisting of a single joint, and very beautifully feathered on its edge. 



Fig. 10. Figures of the natural size and magnified, shewing the progress 

 of developement in the Ova. a, ova when first received into the valvular 

 pouch, h, side and front views of the elongated ova, with its two pair of 

 lateral projections, c, side view of the embryo, the tail considerably elon- 

 Pfated, forked, and bent backwards, and together with the lateral members, 

 slightly ciliated. Fig. 11. The Embryo of the natural size, and magnified. 



