58 THE VOYAGE OF H.M.S. CHALLENGER. 



Museum, a naturalist to whose long continued and conscientious labours all students of 

 the Crustacea are deeply indebted. 



[PL XI. fig. 1, a-e. a Carapace seen from left side, h from right side, c from above, 

 d from below, e from front. Magnified 50 diameters.] 



16. Bairdia crosskeiana, G. S. Brady (PL IX. fig. 3, a-c). 



Bairdia crosskeiana, Brady, Trans. Zool. Soc. Lond., 1865, vol. v. p. 366, pi. Ivii. fig. 10, a-d. 



Carapace elongated, compressed, greatest height equal to about half the length, and 

 situated rather in front of the middle ; seen laterally the outline is subpyriform, wider 

 in front than behind ; anterior extremity obliquely rounded and angulated at its junction 

 with the dorsal margin ; posterior gradually tapering, subacute, and more or less 

 squamously dentated below ; dorsal margin moderately ai'ched, slightly sinuated in front ; 

 ventral margin nearly straight seen from above, the outline is spear-shaped, more than 

 twice as long as broad, widest near the front, tapering abruptly and with a slight sinuosity 

 forwards, very gradually and with a gentle curve backwards ; the anterior extremity is 

 somewhat obtusely rounded, the posterior subacute ; end view ovate, narrowed above, 

 broad below, height considerably exceeding the width. Surface of the shell smooth, 

 marked with closely-set minute punctations. Length, l-25th of an inch (1 mm.). 



Found in the Tongatabu dredging, along with the preceding species ; at Nares' 

 Harbour, Admiralty Islands, in a depth of 1 6 fathoms ; and ofi" reefs at Honolulu, in 40 

 fathoms. 



The southern form as shown by the Challenger dredgings differs from the types taken 

 in the Mediterranean only in being somewhat more slender. My first specimens were 

 found in sponge-sand from the Levant, but since then I have had dredged specimens 

 from other parts of the Mediterranean. 



[PL IX. fig. 3, a-G. a Carapace seen from left side, 6 from below, c from front. 

 Magnified 40 diameters.] 



17. Bairdia ex2oan$a, n. sp. (PL XL fig. 2, a-e). 



Carapace oblong, tumid ; seen from the side, subrhomboidal ; anterior extremity 

 oblicjuely subtruncate, scarcely at all rounded ; posterior much narrower, oblique, some- 

 what squamous, and divided into a few flattened tooth-like processes ; dorsal margin 

 evenly arched, ventral straight ; height equal to more than half the length ; the dorsal 

 view is broadly ovate, not twice as long as broad, widest in the middle, tapering evenly 

 to the extremities, which are mucronate ; end view subtriangular, width slightly exceed- 

 ing the height ; shell-surface perfectly smooth. Length, l-33d of an inch {-77 mm.). 



One specimen only, from a depth of 40 fathoms, off" Honolulu, in company with 

 Bairdia crosskeiana, attemiata and amygdaloides. Apparently quite distinct from 



