121 



November 11. 1834. 



Dr. Marshall Hall, in the Chair. 



A specimen was exhibited of a species of Monacanthus, Cuv., re- 

 markable for having on each side of the body, about midway between 

 the pectoral and caudal fins, a bundle of long and strong spines di- 

 rected backwards. The species was figured in Willughby's ' Historia 

 Piscium,' and a description of it by Lister is contained in the Appen- 

 dix to that work ; but it appears not to have been noticed by subse- 

 quent observers, and to have been altogether overlooked or rejected 

 by systematic writers. Lister's specimen of the Fish was preserved 

 in the collection of William Courten, the founder of the museum 

 which became subsequently the property of Sir Hans Sloane, and 

 eventually formed the basis of the British Museum : that brought 

 under the notice of the Meeting belongs to the Museum of the Army 

 Medical Department at Chatham, and was exhibited with the per- 

 mission of Sir James Macgrigor. It was accompanied by a descrip- 

 tion by Staff-Surgeon Burton, which was read. 



Monacanthus Htstrix. Mon. lateribus in medio 6 — 7-spinosis, 



spinis validis longioribus. 

 Guaperva Hystrix, List., in Will. Hist. Pise, App.p. 21. Tab.S.2\. 



' ' Length 7 inches . Colour black . Skin crowded with rough grains ; 

 a smooth spot behind the gills ; towards the tail assuming the charac- 

 ter of rhomboid scales, but the granular form continued over the caudal 

 fin. On the sides, about one third of its length from the tail, is fixed 

 a cluster of six or seven strong free spines from 4- to 1 inch in length, 

 capable of erection and depression. 



" Dorsal spine very strong, about H inch long, sub triangular, 

 with serrated edges, and grained, except towards the point : when 

 not erected it is lodged in a deep groove on the back. Extremity 

 of the pelvis salient, and terminating in two sharp short spines. Se- 

 cond dorsal fin broad and 2 inches long ; anal similar, but shorter. 



" In front of the eyes a small fossa covered with a membrane, ex- 

 cept in its centre, where it is perforated by a minute olfactory fo- 

 ramen. 



" Teeth in the upper jaw eight, the two middle incisors placed di- 

 rectly in front of the second pair, in a groove of which they are 

 lodged, so that no part of these last are visible externally, except a 

 small process at the cutting edge ; the outer teeth trigonal. The 

 teeth of the lower jaw differ materially from the generic character, 

 their number being only four, of which the two middle ones are 

 by far the largest in the mouth. On this account, and also on ac- 

 count of the nature of its covering, — which partakes of the granular 

 character of that oi Monacanthus and Aluterus, Cuv., and of the rhom- 



No. XXIII. Proceedings of the Zoological Society, 



