472 PROCEEDINGS OP THE ACADEMY OP 



verse diameter, rather narrowly rounded on the dorsum, compressed convex 

 on the sides, and provided with a shallow concavity along the ventrum for the 

 reception of the inner whorls. Septa moderately distant, and deeply divided 

 into six lobes and six saddles ; dorsal lobe longer than wide, infundibuliform, 

 and acutely pointed ; dorsal saddle as long as the dorsal lobe, but wider, and 

 rounded at the end ; superior lateral lobe halbert-shaped, a little longer than the 

 dorsal lobe, and sharply pointed at the extremity : lateral saddle longer and 

 narrower than the dorsal saddle, linguiform, and regularly rounded at the 

 summit ; inferior lateral lobe similar to the superior, excepting that it is some- 

 what smaller ; ventral saddle shorter and broader than the lateral saddle, 

 rather oblique, and rounded at the end. 



Length of an imperfect entirely septate specimen, 2-55 inches ; height, 2-15 

 inches ; convexity, 0-57 inch. 



Locality and position. Rockford, Indiana, from the Rockford Goniatite bed, 

 the exact age of which is somewhat doubtful, though it is generally considered 

 of upper Devonian age. 



Note. In the last number of the Proceedings of the Academy, we described 

 a new Echinoderm, under the name of Melonites Dance, mentioning, at the same 

 time, that it differs from the type of the genus Melonites, in having only four, 

 instead of eight double rows of pores to each ambulacrum. Since that time 

 we have been led to regard this difference as being of more than specific im- 

 portance, though until other species or better specimens are known, we cannot 

 be quite sure it is of full generic value, especially since these forms seem to be 

 exactly alike in other respects. We therefore now propose to found upon this 

 species a subgenus, under the name of Oligoporus (jtxiytt, few ; and mgo;, opening 

 or pore.) 



We also avail ourselves of the present opportunity to correct the following 

 errata, which were overlooked in correcting the proof of the paper mentioned 

 above : 



Page 382, 15th line from the bottom, for second radial read second radials. 



Page 382, for the 4th, 5th and 6th lines from the bottom, substitute secondary 

 radials 1 X 10 : resting partly on the second, and partly on the first primary radials: 

 or, in the absence of the former, directly on the latter. 



Page 382, insert between the first and second lines from the bottom, Anal 

 plate 1, (known); varying much in size and form. 



Page 386, 12th line from the bottom, for Actinocrinus scilutus, read Actinocri- 

 nus scitulus. 



Page 389, 2d, 5th and 23d lines from the bottom, and 4th and 5th line from 

 the top, for Forbsiocrinus, read Forbesiocrinus. 



Description of a New Species of Exocetus, from Chili. 



BY CHARLES C. ABBOTT. 



Exocetus Chili en sis, Abbott. Spec. char. Head of medium size, 

 without scales, and trigonal. Body much compressed and tapering to 

 the tail; peduncle of the tail very slender. Eye unusually large, circular, 

 diameter entering two and two-thirds times in the length of the side of 

 the head; the orbits are one diameter distant. The posterior extremity 

 of the maxillary bone extends to a vertical line drawn anteriorly to the 

 anterior margin of the orbit. The nostrils are situated anteriorly to the 

 eyes, and are about three diameters distant. Anterior to, between, and 

 posterior to the orbits, are numerous pores, with channelled, slender 

 depressions over the forehead and occiput, leading to the orifices of these 

 pores. A well-defined, carinated row of scales commenoe, on each side, at 



[Oct. 



