NATURAL SCIENCES OF PHILADELPHIA. 81 



Acanthopterygii. 



Chirostoma s i c c u 1 u m, sp. nov. 



Mandible scarcely longer than premaxillary ; mouth extending four-fifths the 

 distance to opposite anterior border of orbit; muzzle conic. Eye 3 timesin 

 length of head ; head five times in length to base of tail. Scales small, in six- 

 teen longitudinal and eighty-five transverse rows. Origin of first dorsal oppo- 

 site origin of anal, equidistant between base of caudal and anterior border of 

 orbit. Tip of pectoral reaching ventral. Dorsal outline from end of muzzle 

 to end of second dorsal plane. D. V. 12. A. 25. V. 15. P. 10. Length to 

 base of caudal 



Color in spirits pale brown, (probably translucent in life), the silvery band 

 traversing the 7th row of scales from the dorsal, covering one and two half 

 rows. Top of head, and median dorsal region punctulate with black ; opercula 

 silvery. 



From Grosse Isle, Detroit River. Prof. Fox. 



Gasterosteus inconstans Kirtl.* Grosse Isle. Prof. Fox. 



Specimens labelled as having been brought from Sukertoppen, Greenland, 

 by Dr. I. I. Hayes, appear to belong to this species. 



Potamocottusf a 1 v o r d i i Cotlus, Girard, Monogr. Cottoids. Smiths. Contr. 



Several specimens, agreeing in all points with Girard's description of a 

 young individual except in the position of the vent; the latter is invariably 

 considerably nearer the base of the caudal than to the symphysis mandibuli 

 most nearly median in the smallest specimens. The largest are 3| inches in 

 length. In all I find numerous palatine teeth and a considerable patch of mi- 

 nute dermal spines behind and above the axilla. This species will enter both 

 Girard's Cottopsis, and Gill's Potamocottus ;% but Prof. Gill informs me that he 

 regards the C. asper as the only species referable to Girard's genus, and that 

 the others belong truly to Potamocottus. Similar spinous scales occur on a 



* Gasterosteus micropus is an ally of the incon stans brought from the neighborhood of 

 Fort Riley, Kansas, by Dr. W. A. Hammond. It has a much smaller post-pectoral plate and ven- 

 tral spine, shorter anal and second dorsals, shorter, thicker head, with the bony radii on the upper 

 surface distinct. Length of anal less than from its last ray to end of caudal, and three lengths 

 from the same point reaches the preopercular angle, or hinder margin of orbit. Post-pectoral 

 plate smooth, oblique, concave in front, reaching lower pectoral rays, as long as diameter of orbit 

 longer than smooth ventral spine. Length of muzzle less than diameter of orbit. Belly shield 

 small, twice the ventral spine. Caudal peduncle compressed, smooth. Eye one-lburth length of 

 head ; latter is measured three and two-thirds times in length to base of caudal. D. 4, slender, 

 without plates, 1+10; C.+10+ truncate; A. 1,9, first under second of second dorsal. P. 10. Above 

 blackish, below grey; sides, belly and cheeks densely punctulated with black. 



Near Fort Riley, Kansas ; from the Platte River. Dr. W. A. Hammond. 



f The Academy's museum possesses a specimen of a Greenland Cottid, which appears to be a 

 second species of the genus Triglops. It may be called T. pleurostictus, and defined as follows : 



Head above a line drawn along the suborbital bones, and back above the latpral line covered 

 with minute scales. Eye 3j- times into head ; interorbital breadlh less than half orbit, concave; 

 parietal region concave, with a knob on each side. A transverse depression across the line of the 

 posterior nares. Four preopercular spines, two directed backward, one downward and one for- 

 ward. Mouth horizontal, mandible longer, end of maxillary opposite hinder margin of pupil, On 

 each side, opposite each interval between each dorsal ray, a patch of naked skin imitating a shield ; 

 on each side of the fin a row of tubercles extending to middle of second dorsal. Lateral line with 

 ctenoid plates, whose free posterior borders are continuous with the numerous vertical lateral 

 series of small contiguous ctenoid scales; these give an appearance of the existence of the lateral 

 plates seen in some species of Gasterosteus; several transverse rows of similar scales in advance of 

 the ventrals. The body from the middle of the second dorsal to caudal is depressed cylindrical. 

 Pectorals extending much beyond vent to anal fin : ventrals reaching vent ; latter with a large 

 papilla. Branchiostegal membrane continuous, rays six, (seven in pingelii). Head enters 

 three and three-fourths times in length to base of caudal ; greatest depth five times. Rays, D. XI. 

 2. 4. C. 11 full rays; fin small. A. 27 (24 p i n g elii) V. I. 3 (5 pinge lii) P. 18, the rays rough- 

 ened. Total length 4 in. 9 lin. 



General color brown, darkest above; silvery from vent to branchiostegal membrane, and behind 

 and in front of pectoral fin. Sides pale chestnut ; a band of sienna streaks from opposite middle 

 of pectoral to base of caudal, interrupted by silver spots and lines. 



From Godhaven, Greenland, (Coll. No. 114). 

 t Proc. Bost. Soc. N. H. 



1865.] 6 



