EEPOET ON THE CRUSTACEA MACRURA. 177 



sightless. And recently a young specimen of Homarus has been taken in the English 

 Channel that corresponds with the description of Nephropsis in most points, except 

 that it has well-developed organs of vision, and that the retina at the back of the lenses 

 is lined with black pigment. 



Geographical Distribution. — The Challenger brought home specimens of this genus 

 from Bermuda and from the Papuan Seas. 



Mr. Wood-Mason records his specimens from the Andaman Islands, in the Gulf of 

 Bengal. The Bev. Dr. Norman has described a new species, Nephropsis atlantica, 1 with 

 small and immature eyes, obtained by Mr. Murray in the Fseroe Channel, during the 

 cruise of the " Knight Errant " and of the " Triton." 



But for the absence of the scaphocerite from the second pair of antennae, I should be 

 much inclined to believe' that the species of this genus are only young forms of 

 Nephrops or of some nearly allied genus. The specimen that I described as Nephropsis 

 comubiensis, in the report of the British Association for 1880, with the reservation, 

 " but as we know so little of the young of any of the Macrura after they have passed the 

 earliest stages, we are induced to believe it to be no other than an immature condition of 

 Nephrops" I have recently been able to determine to be a stage in the development of 

 Homarus mar inns of the European Seas. Now, as Nephropsis suhmi was taken asso- 

 ciated with Phoberus tenuimanus, at Station 191, it is not improbable that the two are 

 the same species at different ages. The Bev. Dr. Norman in writing to me says, " The 

 genus is certainly not the young of Nephrops. I have specimens of Nephrops of 

 very much smaller size than the Nephropsis, and the pleon though very like is differ- 

 ent." But it is remarkable that of all the specimens taken in the cruises of the " Knight 

 Errant" and " Triton," there is no spawn on any. 



The fossil genus Hoploparia is undoubtedly closely allied to this genus, and probably 

 represented it in the ancient seas ; for Hoploparia belli, as figured by Salter and 

 Woodward in their Chart of Fossil Crustacea, and by Bell in his Fossil Malacostracous 

 Crustacea, although of larger dimensions, is very closely related to, and probably is a 

 direct ancestor of the recent species. Our specimens of the genus Nephrop>sis are 

 certainly immature forms, if we may judge from the fact that the external sexual foramina 

 are not appreciable, and we may consequently assume that the internal organs are not 

 fully developed in their present state. All the specimens recorded have been taken at 

 a great depth in the sea. 



Nephropsis stewarti was taken at 300 fathoms; Nephropsis suhmi at 800 fathoms, 

 Nephropsis rosea at 700 fathoms; the temperature ranging from 39°"5 to 50° Fahr. 

 (Wood-Mason), Nep>hropsis atlantica was taken in great abundance in the Fa3i'6e Channel, 

 North Atlantic, and Nephropsis agassizii in the West Indies. 



1 Proc. Roy. Soc. Edin., vol. xi. p. 684, 1882. 

 (ZOOL. CHALU EXP. — PART LII. — 1886.) Fff 23 



