REPORT ON THE CRUSTACEA MACRURA. 357 



fio\ 1). It evidently belongs to a species closely allied to the last, but is a little more 

 advanced. It is T33 mm. in length, and the description I have given above will also 

 do for this, except in the ease of the appendages. 



The ophthaimopoda are large and fungiform, the eye being very broad and the stalk 

 slender. 



The first pair of antennas is single-branched, multiarticulate at the base, and ter- 

 minates in a slender articulus that carries three fine hairs. 



The second pair of antennae is biramose, each branch terminating in three or four 

 long hairs. 



The epistoma is armed with a long spine or tooth that projects forwards, but does 

 not reach to the base of the ophthaimopoda. 



The oral appendages and gnathopoda are developed ; the animal has reached the true 

 Zoea stage, and there is nothing in its appearance or characters excepting the biramose 

 condition of the second pair of antennas that is sufficient to prove that it does not belong to 

 one of the Brachyura. Several transverse lines, posterior to the carapace, define the posi- 

 tion of'the future somites, but no appendages even in the most incipient stage are visible. 



Anton Dohrn, 1 to whom we are indebted as having been the first to discover and 

 describe this remarkable form of Crustacean life, gives in his researches on the structure 

 and development of the Arthropoda, the figure of a specimen taken off Messina during the 

 month of March, which bears a general resemblance to that of the Challenger specimen 

 represented on PI. LXIL, but differs in certain details that are suggestive of a 

 distinct specific origin. The rostrum is smooth and free from spinous adornments The 

 orbital, lateral, and posterior dorsal processes of the carapace are furnished with long- 

 smooth spines, the extremities of which are tipped with three radiating teeth, except the 

 central, which is armed with a series of small lateral teeth, but only on one side. 



The carapace is contracted immediately behind the orbital processes, and enlarged in 

 a line continuous with the lateral margins. 



The somites of the pleon are short and broad, and the caudal fork is armed with six 

 long spines, corresponding in number and position with those of Claus's figure, which 

 possesses one more than that on our specimen. 



The ophthaimopoda are long and have the ophthalmus of not much greater diameter 

 than the stalk, and stand in the same line beneath the orbital processes. 



The first pair of antennas is four-jointed, and terminates in a few simple hairs. 



The second pair is two-branched, the branch representing the scaphocerite being- 

 mult iarticulate and fringed on one side with long hairs. 



The rest of Anton Dohrn's description and figure corresponds wdth the degree of develop- 

 ment shown in our specimen, excepting that the saccular sixth pair of pleopoda is shorter. 



1 Untersuchungen uber den Bau und Entwickelung der Arthropoden, von Dr. Anton Dohrn. Zweites Heft, mit 

 viii. Taleln. Leipzig, 1870. 



