1851.] 317 



accident, my manuscript while oeing sent j-iome, was rendered nearly illegible, 

 and I am now able to recover only a few fragments of it. 1 have thought that 

 the animals observed, were of suflicient importance to warrant the publication of 

 my notes, although not relating to the subjects of my own special researches. 



I had intended to prefix a few observations respecting the geographical distri- 

 bution of organic beings on the Isthmus, but having recently received through 

 the kindness of friends, collections which serve to make a more minute compari- 

 son between the production of different parts of the year, I will postpone for the 

 present, the discussion of the phenomena observed, and merely state a single fact 

 which appears to me of great importance, in considerations regarding the limit of 

 the effects of physical causes. During the month of December, I labored assidu- 

 ously to procure a set of the Coleoptera of the vicinity of Panama, and was sur- 

 prised on looking over my collection, to find a complete absence of the genera 

 known to be confined to the tropics. In fact, with the exception of half a dozen 

 Chrysomelines, there was not a single species which might not have come from a 

 region far north of the tropic. It is known that in the southern part of the 

 temperate zone, the Carabica, Brachelytra, water beetles, &c., which first appear 

 in the spring at northern localities, are most abundant in winter, and this would 

 be naturally explained by the fact that the temperature in that season is most 

 nearly akin to to that of the regions in which they flourish best. But it is a little 

 alarming for the doctrine of physical causes, to find that the same arrangement in 

 the appearance of species, is kept up in a region where climate can have nothing 

 to do in producing these phenomena. 



Ophiolepis Mail. 



1. O. a n n u 1 ata, disco squamis minimis imbricatis dense tecto, radialibus 10 

 paulo majoribus, distantibus ; brachiorum squamis dorsalibus hexagonis, latitu- 

 dine sesqui brevoribus extrorsum angustatis, ventralibus subquadratis, extus sube- 

 marginatis ; scutis buccalibus utrinque subacutis latitudine non longioribus, pos- 

 ticoumbonedepresso, foraminisque marginalibus Sdistincto : brachiis dorsofusco- 

 annulatis, disci diametro l'^^^ longioribus. Long. 4 5J unc. 



Color grayish yellow ; disc brown with closely approximated pale spots ; arms 

 seven times as long as the diameter of the disc, with every fourth dorsal plate 

 dark ; the scales of the disc are very small and imbricated, the radial ones 

 scarcely larger, and widely separated. The oral plates are rounded on the lateral 

 angles, and are not surrounded with papillas ; but from the apex of each, run two 

 rows of small papillae, which follow the inflexed margin of the fleshy part of the 

 disc. The oral papillae are distinct, four on each side. The tentacular pores have 

 each two small scales, the spines are arranged in three rows, their length is equal 

 to the diameter of the arms. This species apparently resembles 0. reticulata 

 MuUer, 95. Oi^lmira reticulata Say (J. Ac. 5, 148,) but the spines are longer. 



2. O. ge m i n a t a , disco squamis minimis imbricato, scutis radialibus magnis, 

 elongatis, per paria valde approximatis, brachiorum squamis dorsalibus latitudine 

 duplo brevioribus, intus subaiigulatis, ventralibus transversis,subpentagonisj scu- 

 tis buccalibus rhomboideis, angulis acutis, angulo aborali truncato: scuto postico 

 umbone nullo, foramine unico apicali notato, brachiis dorsomaculatis, disci diame- 

 tro 6 7'ee longioribus. Long. 3 4 unc. 



