250 RECORD OF CURRENT RESEARCHES RELATING TO 



than simple antennae, and to raise the question as to the possibility of 

 their having been chelate at their extremities. As only the basal 

 portions of these organs are, however, represented, this question 

 cannot be satisfactorily determined. 



The name of Palceojyalcemon is proposed for it. It is characterized 

 by a shrimji-like body, with a thoracic carajiace narrowed but not 

 rostrate in front, and keeled on the back and sides. Abdomen of 

 six segments terminated by an elongated, triangular and pointed 

 telson ; segments arched ; pleura smooth, not expanded nor lobed ; 

 their extremities rounded. Sixth segment bearing caudal flaps, one 

 on each side, composed of five visible elements, the outer four 

 apparently anchylosed to form a single large triangular plate on 

 each side of the telson. Thoracic ambulatory appendages elongated, 

 smooth and filiform, except the ui^joer (second) joint, which is 

 laterally compressed. Abdominal appendages short, the upper joints 

 flattened or convex anteriorly, as if for the attachment of plates or 

 fimbria. Antennae with the basal joints strong and well developed, 

 of large size, much exceeding in strength any of the thoracic limbs. 

 Eye-peduncles short. Type P. Newherryi Whitf. 



This the author believes to be the most ancient Decapod crus- 

 tacean yet recognized, and on that account alone is of great interest. 



The earliest form previously described is Mr. Salter's * Paloeo- 

 crangon socialis, said to be from tlie lower carboniferous limestone of 

 Fifeshire. There is another supposed Decapod, Gitocrangon, noticed 

 by Eichter f from the Upper Devonian, which is mentioned by Salter, 

 but of which he says he is doubtful if it be a crustacean at all. 



Blind AmpMpoda of the Caspian Sea.J — Dr. O. Grimm is led 

 by the discovery of some of these forms in the Caspian Sea, to make 

 some interesting remarks on the extent of the blindness of blind 

 animals and of the modifications undergone by other sense-organs in 

 connection with the loss or impairment of sight. 



The problem of the origin and evolution of blind animals has, as 

 he points out, occupied much attention of late, and two opposite 

 opinions prevail which cannot be reconciled. Twenty years ago one 

 might have been contented with the view that creatures were created 

 blind because they were intended to live in the dark, so that the faculty 

 of sight was unnecessary. Nowadays, however, this notion is sup- 

 ported by few ; the great majority of naturalists recognize in the 

 absence of eyes the result of a residence in darkness by which the 

 visual organ must certainly retrograde, as it is not made use of. 

 Besides Fries' experiment with Gammarus pulex, it is well known 

 that persons who have lived for years in dark prisons have lost the 

 pigment of their eyes, as also that in many blind people the optic 

 nerve has disappeared, i. e. is transformed into a mass which contains 

 no visual nerve-fibres.§ Thus it appears very natural that animals which 



* 'Quart. Journ. Geol. Soc, London,' xrii. (1861) p. 531. 

 + ' Beitr. Paleont. Thiiring.' 



X ' Arch. Naturg.,' xlvi. p. 117. Transl. in ' Ann. and Mag. Nat. Hist.,' 

 V. (1880) p. 85. 



§ Strieker, ' Studien iiber ilas Bcwusstscin,' p, 54. 



