oacnESTiD^. 39 



than the propodos, and is but .slightly produced int'oriuily. The 

 secoud piiii- of gnathopodu are nearly six times as large as the first ; the 

 propodos is more rotund in general form ; the pulm is convex, and 

 fringed \^'ith a row of soHtary short haiis ; and a protuberance marks 

 the point -where the extremity of the dactylos bites, Avhich, when 

 closed, confomis to the palm ; the carpus is not produced infcriorly. 

 The pereiopoda are furnished -with short, stiff, spine-like hairs. 



The animal differs but little in appearance from Orchestia, and, no 

 doubt, has often been mistaken for it, fi-om which, however, it is 

 readily detected by its size and the appreciable length of the upper 

 antennic. 



Tlie mici-oscopic structure of the crust shows also a distinction 

 between the two, although not to any very great extent. The "J" 

 markings appear more numerous, and somewhat different in shape. 

 The whole stnicture is covered vnth. a gi'anular pavement ; but no 

 trace of the original cell-foiTnation is apparent. 



The hairs, though formed iipon the same general type as in Or- 

 chestia, yet exhibit some pccuUarities of form : their apex is sharper 

 and shghtly cui-ved ; and the lateral appendage has a peculiar baccate 

 appearance. 



Taken along the line of coast near ordinarj- tide-mark, probably 

 all round our shores : more abundant than Orchestia. 



Hah. Penzance {Mr. 0. Barlee and Mr. W. Webster) ; Moray 

 Frith {Rev. G. Gordon) ; Falmouth and Tenby {Mr. W. Webster) ; 

 Plymouth (C. S. B.) ; Christiansund {Rathke). 



7. Allorchestes Sayi, n. s. (Plate VI. fig. 5.) B.M. 



Male. — Superior antennae Inferior antennae not half as 



long as the animal ; the peduncle is twice as long as the flagellum ; 

 the penultimate articulation is longer than the ultimate. First 



pair of gnathopoda ; second largely developed, ovate, 



tapering towards the dactylos ; palm oblique, and fiu-nishcd with 

 two blunt denticidar processes. The three posterior pairs of 

 pei-eiopoda robust, scabrous ; dactylos furnished upon the inside, 

 near the middle, with a small hair. 



Length ^ths of an inch. 



The figure, together with the above description, is taken from one 

 of two or three unnamed damaged specimens in the Collection of 

 the British Mnseum labelled " Say," being some that were presented 

 by Professor Say. 



Hub. North America {Saij). 



8. Allorchestes microphthalmus, n. s. (Plate VI. fig. 0.) B.M. 

 Gammarus microphthaliuus, MiS. Brit. Miis. 

 Eyo8 minute, round ; they appear to >)c only small si)ecks ; but 



