GAMMA RID.E. 133 



inferior. IMoon liaving the anterior segments earinated and pos- 

 teriorly produced into teeth. Posterior pair of pleopoda ha\ing 

 the rami subequal, foliaccous, lanceolate. Telson absent (?). 

 " Length 4 lines. 



•' Hab. Dronthcim." — Rathlce. 



On a comparison of the parts ligiired by Rathke with tho.se of 

 JJcvamine sjjinosa, the only observable ditt'erence is the absence of 

 the tooth at the inferior distal exti'emity of the fii*st joint of the 

 ])i'dnncle of the .superior antenna\ In his description, Kathke says 

 that there is no telson ; and, .singularly enough, Montagu publi.shed 

 his tigiUT of Came)- (Gamma run) sj^jinosiis without this appendage, 

 as also Prof. Milne-Edwards his figure of Amphitofi Marionis. 

 The telson is long, slender, articulated upon a process, and very 

 liable to be dislocated. Certainly Rathke's icnuiconiis is very closely 

 fdlied to, if not identical with, Montagu's sjiinosiis. 



5. Dexamine tricuspis. (Plate XXIV. fig. 5.) 

 Acauthonotus tricuspis, Kroyer, Voij. en Scand. pi. 18. f. 1 a. 



Cephalon produced into a small rostrum. Last segment of the pereiou 

 and the first two of the pleon each dorsally produced into a tooth ; 

 tliird segment of the pleon having the posterior lateral margin 

 ornate. Eyes small. Sujierior antenna) as long again as the 

 inferior. In other respects the figiu-e of the animal from wliich I 

 have taken this description appears not to differ materially from 

 D. spinosa. 



Length ? 



Hah. Arctic Europe (Kroyer). 



39. ATYLUS. 



Atvlus, Leach, Zoohxjical 3IisceUa)ii/, ii. pi. 69. 



Hthciirds, Hist, ilcs Crust, iii. p. (57. 

 Iphiinidia, Dana, V. S. Exphir. Exped. p. 92G. 



Notrotopis, Costa, Rend, del/a Reale Accad. delle Scienze di Napoli, 

 p. 170, 1853. 



Animal compressed. Antcnnoe subequal ; superior without a se- 



condaiy appendage. Mandibles with an appendage. Maxillipeds 



unguiculate, having a s<]uamiform plate developed from the bases 



and ischium. Gnathopoda subchelate. Pereiopoda subequal. 



Posterior pleopoda biramoits. Telson single, squamiform, divided. 



ITie above generic description is taken from Leach's type, which 

 is preserved in tlie British Museum. 



Atiflus fhtters from Dexamine in having the third joint of the pe- 

 duncle of the upper antenna; distinguishable from tlie tlagellum, and 

 in having an appendagi- to tlie manchblcs. 'I'lio species of this 

 genus are generally remarkable for some pecidiarity connected w itb 

 the Hagolla of the antenna?. 



