S12 Zoological Society. 



in form, being one inch and a half long and half an inch wide at the 

 base, whence it gradually tapers throughout its whole length to the 

 tip. The spur on the shoulders is strong and sharp, and is nearly an 

 inch in length. 



The Fishes were characterized by Mr. Bennett, who remarked on 

 the complete analogy borne by these species of the rivers of Western 

 Africa to some of those of the Nile. The form of Myletes, Cuv., to 

 which Lieut. Allen's fish belongs, has hitherto been obtained only in 

 Egypt j the genus Polypterus, Geoff., originally observed in the 

 Nile, seems to be limited to that river and to Senegal ; the genus 

 Gymnarchus, Cuv., has previously been noticed only in the Nile; and 

 the Tetrodon of this collection resembles in its markings that of 

 Egypt. The new species were characterized as Myletes Allenii and 

 Tetrodon strigosus. 



The exhibition was resumed of the new species of Shells collected 

 by Mr. Cuming on the western coast of South America and among 

 the islands of the South Pacific Ocean. Those brought on the pre- 

 sent evening under the notice of the Society were accompanied by 

 characters by Mr. G. B. Sowerby. They belonged to the genus 

 Petricola, and were named as follows : 



Petric elliptica, oblonga, solida, discors, concinna, denticulata, 

 rugosa, tenuis, robusta, and amygdalina. 



The following " Description of a new Genus of Gasteropoda, by 

 W.J. Broderip, Esq., Vice President of the Geological and Zoological 

 Societies, F.R.S., &c." was read. 



SCUTELLA. 



Testa Ancyliformis, intus nitens. Apex posticus, medius, invo- 

 lutus. Impressiones musculares duse, oblongo-ovatse, laterales. 

 Apertura magna, ovata. 



Animal marinum. 



This genus appears to be intermediate between Ancylus and Patella, 

 while the aspect of the back sometimes reminds the observer of Navi- 

 cella or Crepidula, Lam. Its place will most probably be among 

 the Cyclobranches of Cuvier. 



The two muscular impressions are situated on each side of the in- 

 terior a little below the summit j while, in Patella, they nearly 

 surround the internal circumference of the same part of the shell. 

 The aperture is generally surrounded by a margin, and the apex, 

 which in Ancylus is oblique, is central though posterior. 



Mr. Cuming brought home the following species which I now pro- 

 ceed to describe. 



Scutella crenulata. Scut, testa subeonicd, cancellatd, striis ab 

 apice radiantibus exasperatis, albd ; int-us nitente ; annulo mar- 

 ginali et margine crenulatis : long, -g- , lat. £, alt. T V poll. 



Hab. ad insulam Aniian (Chain Island). 



This shell was found dead on coral sand on the beach of the island 

 at a distance from any fresh water. 



The marginal ring is very strongly developed, and the margin it- 

 self is not even j for when the shell is placed with the aperture down- 

 wards on a flat surface, it rests on the two ends, the sides of the 

 margin forming each a low arch. 



