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



in the Atlantic and South Indian Oceans at an approximate depth of about 2000 

 fathoms. 



The specimen taken at Station 104 carried from thirty to forty eggs of an ovate 

 form and large size, in which the embryo is present, sufficiently advanced to demonstrate 

 the character of the brephalos to be that of the Megalopa stage. 



The specimen from Station 87 has the dorsal crest almost smooth, the small 

 denticles being either in a rudimentary condition or broken off by friction. In this 

 specimen the outer plates of the rhipidura are preserved, and close inspection, even after 

 the application of a reagent, failed to show the presence of a diaeresis, and the small tooth 

 on the outer margin that demonstrates its position when present is wanting, although a 

 small notch shows its position. This is also the condition in the two specimens taken at 

 Station 157. In one of these the animal was not far from the point of moulting. The 

 form of the plate is rounded at the extremity, and almost smooth, or where more highly 

 magnified shows small indentations from which hairs have been removed, and a small 

 denticle is present at the outer angle. Within the cuticle the new dermal structure is 

 in an advanced condition, and exhibits the presence of long slender hairs along the distal 

 margin, and the outer angle bears, not a minute denticle, but a long hair and a strong 

 spine, beyond which the outer margin is smooth, although in some specimens a series of 

 small dots are regularly placed, suggesting the presence of a number of minute hairs on 

 the under side within the margin. 



In one of the two specimens from Station 133 the telson is tolerably preserved, which 

 is not the case in the type specimen. It is longer than the lateral plates of the rhipidura, 

 and nearly twice the length of the sixth somite, and probably terminates in a few hairs of 

 greater or less length, but which are broken off. 



Family Stylodactylid^e. 



This family is established to receive those forms, of which only one genus is known, 

 in which the first pair of gnathopoda terminates in two branches, subequal in size and 

 importance, and the propodos of the two chelate pereiopoda has the palin short and the 

 pollex and dactylos long, slender, and feeble. 



Stylodactylus, A. Milne-Edwards. 



Stylodadylus, A. Milne-Edwards, Ann. d. Sci. Nat, ser. 6, tom. xi. p. 11, 1884; Recueil de Fig. 

 Crust, nouv., 1883. 



Carapace one-third of the length of the body, dorsally rounded, anteriorly compressed 

 to a slight carina, and produced to a long, slender, and laterally compressed rostrum, 



