5778 Crustacea. 



not more than two tides out of thirty enter them. The water is fre- 

 quently quite warm to the touch ; yet in it a well-marked variety of 

 this shrimp abounds. This variety is smaller in size (about one-fifth 

 less), the beak always ending in a single point, and much deeper and 

 shorter ; the hands are more slender ; but in other respects the ani- 

 mals appear identical. This variety has been figured in Desmarest's 

 ( Consideration des Crustaces ' as P. varians, but is distinct from that 

 species here, the blue and orange bands of the legs separating it 

 easily. Spawns all through the summer. Ova brown. Local name 

 " Shrimps." Although found in such abundance, it is never brought 

 to market. This is the species alluded to by Rutty as destroyed by 

 the frost of 1740, and not P. serratus as W. Thompson states. 



Varying Prawn (Palaemon varians, Leach). In sand-pools at Mer- 

 rion, rare. Easily distinguished from the last by the total absence of 

 all coloured bands on the hands, &c. It is more restless in a viva- 

 rium than P. Squilla, but easily reared. I have had it for the last five 

 months. 



Varying Opossum Shrimp [Mysis ChamceIeo?i, J. V. Thompson). 

 Extremely abundant in sand-pools from March to September, when 

 it spawns. Rare near the shore, at other times also in Zostera pools. 

 The ova, which are pale yellow, are easily hatched. 



Common Opossum Shrimp (Mysis vulgaris, J. V. Thompson). 

 Common in strand-pools all the year round at Merrion. Abundant 

 in the tide-way of the Dodder. Spawns the same time as the last. 

 Not so common in the deeper pools. 



Mysis ? A small species, distinct from the M. Chamaeleon, 



abundant in Zostera pools, which I think may be Mysis Lamornae; 

 but further investigation is required. 



The following species are recorded as having occurred about Dub- 

 lin ; but living specimens have not come under my notice : — 



Three-spined Shrimp [Crangon S-spinosus). Looking over a col- 

 lection of small Crustacea collected by the late Dr. Robert Ball and 

 Prof. Forbes off Skerries, in 1845, I found three specimens of this 

 shrimp previously unrecorded as Irish. 



Spiny Lobster or Sea Cray-fish {Palinurus vulgaris, Leach). Rare, 

 but has been captured at Dalkey, in lobster pots and on long lines ; 

 also at Bray. Though I have never seen a specimen thence myself, 

 there can be no doubt of the fact. Occasionally brought to market 

 here, chiefly from the West, but not much esteemed. Local name 

 " Crawfish." 



