REPORT ON THE CRUSTACEA MACRTRA. 185 



a development so different. A parallel ease, however, is to be found in the Alphseidse, in 

 species so closely resembling each other in adult characters as to be scarcely distinguish- 

 able, and yet producing the brephalos in the separate forms of a Zoea and a Megalopa. 



Geographical Distribution. — Hitherto there has been only one species of Nephrops 

 known, and that appears to be confined to the northern European seas from the Irish 

 coast to the shores of Scandinavia. Milne-Edwards adds the Adriatic, but I know no 

 other authority for the Mediterranean habitat. Our new species, Nephrops thomsoni, was 

 taken, the male near the Philippine Islands, the female near New Zealand ; so that it 

 appears to have a tropical and subtropical range in the Pacific and Indian seas. 



The genus appears to be represented geologically, according to Milne-Edwards, by 

 Astaxus leachii, Mantel! 1 It agrees closely with some forms of Hoploparia, while 

 others approach that of Homarus, most of which come from the Green Sand and 

 from the London clay-beds. 



Nephrops thomsoni, n. sp. (Pis. XX V., XXVL). 



Carapace produced anteriorly to a long sharp-pointed rostrum, the margins of which 

 are dentate and continued in a ridge nearly to the cervical fossa. Antennal tooth very 

 large and strong. First pair of pereiopoda long, slender and subcylindrical ; carpos 

 having two or three teeth on the outer and one on the inner distal margin ; meros armed 

 with one outer and one inner tooth on the distal extremity. The two succeeding 

 pereiopoda are short and very slender and terminate in small chelae ; the two posterior 

 have the dactylos long and styliform. The outer ramus of the rhipidura has a delicately 

 crenated diseresis. Telson quadrate. 



Habitat.— Station 166, June 23, 1874 ; lat. 38° 50' S., long. 169° 20' E.; between 

 Australia and New Zealand ; depth, 275 fathoms ; bottom, Globigerina ooze ; bottom 

 temperature, 50°"8. 



Length (female) including rostrum, 138 mm. (5 - 5 in.). 



Station 204a, November 2, 1874 ; lat. 12° 43'N, long. 122° 9' E. ; between Samboangan 

 and Manila; depth, 100 fathoms ; bottom, green mud ; temperature not recorded. 



Length (male), 125 mm. (5 in.). 



The carapace from the frontal margin is one-third of the length of the animal. The 

 rostrum is half as long as the carapace, sharply pointed and slightly elevated anteriorly, 

 armed with one strong anteriorly-directed acute tooth on the under surface, midway 

 between the eyes and the apex, also with two similar teeth on each side on the upper 

 surface anterior to the eyes, from which a strong ridge passes backwards on each side 

 to near the cervical sulcus or the posterior extremity of the gastric region of the cara- 



" ; ' Geol. of Sussex, p. 221, pi. xxix. figs. 1, 4, 5, ; Clytia leachi, Eeuss, Denkichr. d. k. Akad. Wiss. Wien, BJ. vi. t. 5, 

 1854. Restored in Salter and Woodward's Chart of Fossil Crustacea, 1865. 



(ZOOL. CHALL. EXP. PART LII. 1S86.) Fff 24 



