306 PAL^MONlDyE. 



the number alone, although very constant, scarcely con- 

 stitutes so true and certain a criterion as the fact that of 

 the upper teeth two are invariably placed on the median 

 line of the carapace, posterior to the base of the rostrum, 

 and the third immediately over the margin of the ocular 

 notch. The upper teeth are very acute, spiniform, and 

 directed very much forwards. Those of the under side are 

 broader at the base, triangular, and the posterior one 

 slightly falcate. The apex of the rostrum is bifid, the 

 inferior point being the longer. 



Of fourteen specimens examined I found the teeth on 

 the upper and under side of the rostrum as follows : — Seven 

 had f, five |-, one |, and one 1, so that the normal number 

 is i or f . 



The total length, from the rostrum to the tail inclusive, 

 of the largest specimens I have examined, was two inches 

 one line. 



This species is pretty widely distributed along our 

 coasts. I have obtained it from Ireland through the kind- 

 ness of Colonel Portlock ; and Mr. W. Thompson records 

 it as common on the shore of Belfast Lough, in rock pools, 

 on the Down coast, as well as in deep water. He also 

 mentions having met with it commonly in rock pools about 

 Ballantrae, Ayrshire. It occurs on the Cornish and Devon- 

 shire coast, but Mr. Couch considers it rare in the former 

 county, although Dr. Leach mentions it as very abundant 

 in the latter. At Poole, in Dorsetshire, it forms a con- 

 siderable proportion of the " cup-shrimps," a name given 

 there to the young prawns of three different species, which 

 are sold by measure. 



