238 Mr. W. Thompson's Additions to the Fauna of Ireland. 



The questions occur : — is the &. tenuirostris a deep-water, a local, 

 or a geographical variety ? The following remarks, though all that 

 can be given, have not any very definite bearing on these points. 

 Leach mentions it as a very common inhabitant of all the deep water 

 off the coast of South Devon. Couch in his ■ Cornish Fauna,' part 1. 

 p. 64, states that it is " common at the depth of from two to twenty 

 fathoms *." M. Edwards says of S. longirostris\, Fabr. (sp.), which 

 he makes synonymous with S. tenuirostris, Leach — but Mr. Bell 

 thinks that they may be distinct — that it inhabits the Manche and 

 the Mediterranean. 



S. phalangium is noted by Leach as M very common in the mouths 

 of rivers and in estuaries." Couch has never met with it on the 

 coast of Cornwall. M. Edwards notes it as very common on the 

 coasts of the Manche and the Ocean. 



2. Eurynome scutellata, Risso. 



A specimen of Eurynome dredged on the same occasion as the 

 last species having exhibited the tubercles on the cardiac region — 

 the ten noticed by Bell, p. 47, as ranged round the central one — 

 massed together in the form of a shield or escutcheon, and the series 

 anterior to them on the central line (longitudinally) of the carapace 

 having presented a similar appearance, suggested the specimens 

 being the E. scutellata, Risso. This indeed was rather indicated by 

 the name of the species than by any particular definition in the 

 description of it : — " De petits £cussons arrondis, rouge et jaune 

 pale, couvrent le test de ce joli crustacej." On examining other 

 specimens in my collection and finding great diversity as to the 

 isolation and approximation of the tubercles so as to form shields in 

 the different individuals, I became certain that the E. aspera and E. 

 scutellata are but one species, the latter being a state of the former 

 with the tubercles drawn together so as to form shield-like patterns. 

 The shields in all the specimens examined, except the first-men- 

 tioned, show that they are formed by the junction of the tubercles : 

 in it however no trace of the separate tubercles is visible, but instead, 

 the five on either side the central one on the cardiac region are all 

 fused together. Those forming the smaller shield anterior to it are 

 likewise fused together so as to leave no trace of the number of 

 tubercles forming it. 



Having understood that my friend Professor Bell had authentic 

 specimens of E. scutellata from the Mediterranean, I compared my 

 specimens with them, and found a perfect identity as to species. He 

 had considered the E. scutellata as distinct, but when my reasons 



* S. phalangium proper is taken in the north of Ireland within this range 

 of depth. 



f The only character given for this species in M. Edw. ' Hist. Crust/ 

 vol. i. p. 280, is that the rostrum exceeds in length the peduncle of the ex- 

 ternal antennae. 



X Risso, ' Hist. Nat. de l'Eur. Merid.' vol. v. p. 21. M. Edwards considered 

 the E. scutellata to be so unsatisfactorily described that he could make 

 nothing of it. (Hist. Crust, vol. i. p. 352.) The figure too is execrable. 



