SriflULA. MOLLUSCA. CEPHALOPODA. 22' 



CEPHALOPODA. 



NAUTILIDiE. 



Gen. I. SPIRULA. — Whorls regularly involute, separate ; 

 mouth orbicular; partitions concave, perforated by a proxi- 

 mal continuous pipe. 



1. S. australis. — Shell with fine smooth whorls; partitions 

 slightly depressed externally. 



Nautilus exiguus, albus, pellucidus, teres, Lister, Conch, t. 550. f. 2.— 

 Naut. Spirilla, Linn. Syst. i. 1163 — Turton, Conch. Diet. 11? — West 

 coast of Ireland. 

 Shell about an inch in breadth. The first chambers, at the apex, are a lit- 

 tle inflated ; but, as they gradually increase in size, in the outer whorls, their 

 surface becomes more even, and the line of separation less distinct ; partitions 

 perlacious. The last chambers are nearly cylindrical, and produced in a 

 straight line. According to Lamark, (Histoire Naturelle des Animaux sans 

 Vertebres, vii. GOO.), the shell is imbedded in the posterior extremity of the 

 sac, a portion only of the last whorl being visible. The head is surrounded 

 with eight arms and two feet. Two specimens of the shell of this animal 

 were found on the strand between Kenmai'e Harbour and BallyskeUegs Bay, 

 in the county of Kei-ry, by Mr O'Kelly of Dublin, in the summer of 1817. 

 It is probable that the remains of many other animals, the ordinary inhabi- 

 tants of the West Indian seas, will occasionally occur on the Irish coast, as 

 in the present instance ; but we have to determine their capability of living in 

 our seas before their right to a place in our Fauna can be established. The 

 claims of the present species are doubtful. 



Gen. II. SPIROLIN A.— Whorls contiguous. 



2. S. subarcuatida. — Outer margin carinated ; inner margin 



rounded ; partitions of the chambers raised on the sides. 



Naut. subarcuatus, geniculis exertis. Walker, Test. Min. t. iii. f. 73. 

 Mont. Test. Brit. Sup. 80. t. xix. f. 1. — Sheppy Island, rare ; Mr 

 Walker. 



Size about one-eighth of an inch. Chambers widest externally, making 

 the margin of the mouth oblique ; about twelve in number, the last four 

 forming the produced portion. Syphon near the inner or proximal margin. 

 When the produced portion is broken off, the remaining convoluted part is 

 considered by Montagu as having been figured by Walker, at t. iii. f. 66. 



3. S. semilitua. — Outer margin rounded; the partitions of 



the chambers raised on all sides. 



Nautilus sem. Mont. Test. Brit. 106. Sup. SO. t. xix, f. 3 Sandwich and 



Sheppy, ]Mr Boys.— Rare. 



