216 



THE VOYAGE OF H.M.S. CHALLENGES. 



whereas the character and arrangement of the branchias clearly demonstrate its approxi- 

 mation to the Astacidea. Mr. Miers, in his short Memoir published in the Linnsean 

 Society's Journal, has followed the same classification, having been led to this 



arrangement by the three anterior pairs of pereio- 

 poda being chelate, somewhat as they are in Penseus. 



Among the numerous specimens captured some were 

 carrying ova, and as those of one specimen had the 

 embryo far advanced in development, I am able to give 

 a description and a figure of the brephalos (PL XXIX. 

 fig. 2), which may be compared with the annexed wood- 

 cut from a drawing of Dr. v. Willemoes-Suhm's, taken 

 from the recently hatched animal. 1 



The eyes are large, and in the embryonic condition 

 sessile. The anterior antennas are uni-branched and 

 terminate in a small joint or lobe. The posterior 

 antennas are two-branched, standing on a robust base 

 or peduncle, about half the length of the first joint of 

 the first pair ; the oral appendages are visible, and the 

 two pairs of gnathopoda are biramose and well ad- 

 vanced in structure. The several somites of the pereion 

 and pleon are defined, the anterior ones being very 

 short, and the posterior long, the last or telson is the 

 longest, and terminates in a bifurcate or fish-tail 

 extremity, having the posterior margin crenated and 

 fringed with five long hairs on each side, and the 

 lateral angles defined by a sharp tooth. 

 This, so far as I am able to determine, bears some resemblance to the animal which 

 Claus 2 has figured as the Protozoea stage of Penseus, but which has not yet been fully 

 determined. 



Habitat.— Station 209, January 22, 1875 ; lat. 10" 14' N., long. 123° 54' E. ; off 

 Zebu, Philippines ; depth, 95 fathoms ; bottom, blue mud ; bottom temperature, 71°. 

 In a sjliceous sponge (Euplectella). 



Fig. 42. — Zoea of Spongicola venusta, from 

 a drawing by Dr. v. Willemoes-Suhm. 



1 In a letter to Professor von Siebold (Zcitschr.f. wiss. Zool., Bd. xxvi. p. lxxiv., 1876), Dr. v. Willemoes-Suhm says, 

 ' ' Palcemon sp.,' parasite inhabiting Euplectella. Very transparent and delicate species. I succeeded to get the Zoeas 

 out of the eggs, by keeping the mother in a globe, and found that the young one is an ordinary Zoea in which, 

 however, some appendages are to be seen which, as a rule, come out only in a later stage." None of these have 

 reached me among his numerous specimens of the kind, and Mr. Murray, in writing to me, says, " I cannot find any 

 preparation of these Zoeas ; in fact it is by no means sure that Suhm made any." 



2 Carl Claus, Crustaceen-System, Taf. ii. fig. 1. 



