New Subgenus of the Laniad<z. 487 



type. In this shell, which offers another instance of irregularity in the 

 disposition of the last whorl, instead of the whorl being bent out of the 

 axis, the animal, a short time before it is about to complete its shell, 

 produces the front of the mouth, and then, after having suddenly enlarged 

 the size of the whorl, as suddenly turned round, taking care to keep it 

 attached to the proper part of the penultimate whorl, half a turn, and then 

 completes its mouth, thus keeping of the larger whorl on the one before 

 it; and the prominences produced by the enlargment of the mouth at 

 the last stoppage of the growth giving the shell, and especially the last 

 whorls, a depressed, angular, distorted appearance. 



The two new species here described were discovered by Mr. Speck, a 

 very industrious collector, who has just returned from Sierra Leone, and 

 communicated to me by my intelligent friend Mrs. Mauger of Clapton. 

 With them, besides many other marine shells, he brought a specimen of 

 Achatina which, as it appears to be new, and offers some peculiarity in its 

 structure, I shall proceed to describe, under the name of 



Achatina clavdta, Shell lanceolate, thin, pellucid, white. Whorls 1 1 or 

 12, rather convex, closely concentrically grooved ; last with a spiral slightly 

 raised keel, and smooth in front ; the apex club-shaped, with more distant, 

 sharp, and elevated ridges. 



Inhabits Sierra Leone. Mr. Speck, collection of the British Museum, 

 Mrs. Mauger's, and my own. 



This species is most allied to my Achatina sulcata but much larger, and 

 very distinct, from the peculiar club-shaped form of the tip. 



Art. IX. Description of a netv Subgenus, and some Remarks on 

 Birds belonging to the Family Lariiadce. By George Robert 

 Gray, Esq. 



Genus CHAUNONCTTUS* G. R. Gray. 



Gen. Char. Rostrum capite longius, validum, basi latum, apice attenuatum, 

 vix dentatum ; culmen latum, laeve, rotundatum, basi lunulata ; nares 

 nudi, in medio rostro, laterales, immersi, oblongi; plumis aperturam 

 attingentibus. Alae subrotundata?, breves, remigibus lma, 2da, 3tia gra- 

 duatis, 4ta, 5ta, Gta subaequalibus longioribus. Tarsi rostri longitudine ; 

 digitis Malaconoti sed brevioribus; unguibus brevibus vix curvatis. 

 Cauda mediocris, leviter rotundata. 



Chaunono^tus Sabi'nii G. R. Gray. Sabine's Puff-back. 

 C supra caerulescenti-niger; dorsi plumis floccosis mollissimis et subtus 

 albis. 

 Thamnophilus Sabini J. E. Gray's ZooL Misc., i. p. 7. 



The total length of this bird is 8 in.; that of the bill, 11 

 lines; of the culmen, 10 lines; of the wing, Sin. ; of the 

 tarsi, 11 lines. 



The two specimens that I have before me were brought, 

 some time ago, from Sierra Leone, by Captain Sabine, R. A., 

 after whom my brother named them. As they were unac- 

 companied with any remarks, I am unable to furnish an ac- 

 count of their habits ; but the shortness of their toes renders 

 it probable that they are more terrestrial in their mode of life 



* Chaunosy swollen; notos, back. 



N N 4 



