154 Miscellaneous. 



genera of Bivalves ; and at the same time it shows how careful Nature 

 is to do nothing in excess ; for it must be plain to every one, that while 

 a free oblong shell will require two abductor muscles to keep the 

 valves in their place with regard to each other, a more or less orbi- 

 cular shell attached by the outer side of one of its valves will only 

 require a single subcentral muscle to effect the same object. 



It appears to me that the genus Acostcea is only a synonym of 

 the genus Millleria of Ferussac, and that it and Etheria must be re- 

 ferred to the same family ; and I have no doubt that when the young 

 shell of Etheria has been observed, it will resemble that now first 

 observed on the tip of Acostcea. The one is an African, and the other 

 an American genus. 



Notice of the Sea Bream, Pagellus centrodontus, Ciev., taken in the 

 Firth of Forth. By John Alexander Smith, M.D. 



A very beautiful specimen of the sea bream, Pagellus centrodontus, 

 Cuv., was taken in a trawl-net off the Isle of May, near the mouth 

 of the Firth of Forth, on Saturday the 29th of November last. It is 

 18^ inches in length to the extremity of its forked tail, breadth across 

 from dorsal to ventral fins about 6 inches. 



Number of fin rays: D. 12 + 13; P. 17; V. 1 + 5 ; A. 3+13; 

 C. 17. 



Dorsal fin brown, edged with red ; pectorals nearly 5 inches in 

 length, and like tail of a red colour ; ventrals gray, with large red 

 spot in centre ; and anal gray, with longitudinal red stripe. 



Teeth nearly equal, sharp and pointed in front and edges of jaws, 

 more rounded behind; in four or five rows, the inner the largest 

 posteriorly ; pharyngeal teeth sharp-pointed and thickly set together ; 

 peritoneum lining abdomen of a blackish brown colour ; stomach 

 roundish, rather muscular, contained remains of small fish like her- 

 ring fry ; just beyond pylorus four caeca encircling bowel, one short 

 and others nearly equal ; intestine bent twice upon itself before reach- 

 ing anus ; ovaries rather small ; air-bladder large and undivided. 



It appears to be a very rare fish, or at least to be very rarely caught 

 in our neighbouring seas, as far as I have been able to ascertain. 



On the Circulation and Respiration of the Annelida. 



By M. A. DE QUATREFAGES. 



In the first portion of this memoir, M. de Quatrefages, by the 

 observation and dissection of numerous types, confirms the general con- 

 clusion arrived at by Milne-Edwards in his investigations, namely, that 

 in the circulatory system of the Annelida, the division of the physio- 

 logical labour is carried to very different degrees, from a complete 

 system, furnished with a true capillary network, to that of a blood- 

 vessel which exists only in the neighbourhood of the branchiaj ; it is 

 not impossible that the circulatory apparatus may disappear entirely ; 

 at least this appears to be the result of the observation of some small 



