REPORT ON THE CRUSTACEA MACRURA. 



681 



Length, entire (male), 



„ of carapace, 



., of rostrum, 



„ of pleon, 



„ of third somite of pleon, 



„ of sixth somite of pleon, 



,, of telson, 



39 mm. (l - 5 in.). 

 12 



9 

 27 



5-5 



3 



C 



Habitat.— Station 188, September 10, 1874 ; lat. 9° 59' S., long. 139° 42' E.; Arafura 

 Sea, south of Papua ; depth, 28 fathoms ; bottom, green mud. Two specimens ; males. 

 Trawl and dredge both used. 



This species is remarkable for its smoothness, but when it is in a dry condition the 

 lines of the lateral carinas on the carapace are appreciable, appearing as very slight 

 elevations. One carina corresponds with the orbital tooth, and the other commences 

 at the posterior margin, runs forward and unites with the first on the hepatic region. 

 The dorsal carina is likewise less conspicuous than in the typical forms of the genus and 

 is not elevated into a prominent crest. 



On the pleon the carina is indicated on all the somites, but more especially on 

 the third, fourth, and fifth, where it culminates on each posteriorly in a small sharp 

 tooth. 



The ophthalmopoda are pear-shaped and the ophthalmus hemispherical. 



The first pair of antenna? carries a stylocerite that is sharply pointed and reaches 

 beyond the distal extremity of the first joint, and a fiagellum that is scarcely longer 

 than the rostrum ; the outer fiagellum in the male is much m ore robust than the inner. 

 The second pair supports a scaphocerite that tapers to the extremity and terminates in 

 an external tooth. 



The pereiopoda are rather short ; the three last pairs are serrate on the posterior margin, 

 and each terminates in a long dactylos. 



Observations. — Two specimens of this intermediate form were taken in the shallow sea 

 south of New Guinea. They are interesting as showing the value in classification of the 

 lateral carina and the passage of one form into another. 



The species bears a near resemblance to Chlorotocus gracilipes, A. Milne-Edwards, 

 from the West Indies, and it would, indeed, have been classified in the same genus had 

 not A. Milne-Edwards figured the carpos of the second pair of pereiopoda as being uni- 

 articulate, a character which approximates it to Thalassocans of Stimpson [Regulus 

 of Dana), whereas Dorodotes is structurally nearer Pandalus. 



(ZOOL. CHALL. EXP. — PART Lit. — 1887.) 



Fff 8G 



