134 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



TracMnidae in the method, and we contemplated tlieir insertion at page 38 of this report. 

 When the first portion of our MSS. went to press, however, professional duties diverting our 

 attention from this suhject, a previous pagination brought this family at the present juncture, 

 where we must now give it to the reader. 



We cannot help thinking that the natural affinities of the Batrachidoe with the TracMnidae 

 are more intimate than would ajjpear at first sight, and we should not be surprised if further 

 researches into their structure should favor their union into one single group, for Uranoscopus, 

 or star-gazer, seems to establish a natural transition from the Batracliidae to the TracMnidae. 

 It is anatomically related to the Trachinids by the absence of the air bladder and the presence 

 of pyloric appendages, whilst zoologically it reminds us of Batraclius and allied genera, by the 

 shape of the head and body, the structure and gape of the mouth, and of the fins also: the 

 position of the ventrals being the same in Trachinids and Batrachoids, inserted as they are in 

 advance of the thoracic belt, and hence anteriorly to the base of the pectorals. 



Syn. — Batrachidoe, Swains. Ess. class Fishes Ainph. and Rept. II, 1839. 



The general aspect of the batrachoids is that of a large and depressed head followed by a 

 body more or less tapering, sub-depressed anteriorly and compressed posteriorly, protected by 

 ctenoid scales or entirely scaleless. The branchial apertures are continuous under the throat in 

 Uranoscopus, and widely separated by an isthmus in Batrachus and in Porichfhys. There are 

 four, branchial combs in Uranoscopus, and three only in Batrachus and PoricMhys. The two 

 latter want the sub-orbital bone, whilst the former possesses it largely developed. 



The carpus is very much developed, but all the carpal bones contribute to its development ; 

 besides, the pectorals fins, far from presenting a pediculated appearance, exhibit a broad and 



fan-like base. 



• 



PORICHTHYS, Girard. 



Gen. Ciiar. — Body elongated, tliiekish anteriorly, quite tapering posteriorly. Head smooth, large, and depressed. Eyes 

 rather small. Mouth broad, moderately cleft, with its gape directed obliquely upwards. Lower jaw longest. Canine teeth 

 upon the jaws, front of vomer, and along the palatine bones, Preopercle spinous. Branchial apertures large, extending below 

 the insertion of pectorals, and separated by a wide isthmus. There are six branchiostegals rays on either side. Pectorals 

 spear-shaped. Ventrals inserted in advance of the thoracic arch . Anterior dorsal fin rudimentary. Second dorsal and anal 

 elongated, approximating to, but not united with, the caudal. Skin smooth and scaleless. Several series of mucous pores. 



SiN.—Porichthys, Grd. in Proc. Acad. Nat. Sc. Philad. VII, 1854, 141. 



This genus differs from Batrachus by its dentition as well as by the numerous series of 

 mucous pores which are observed over the head and body. Moreover, the head is smooth com- 

 pared to Batrachus, since there are but few filiform tentacles instead of the membranous flaps 

 which exist in the latter named genus. The branchial apertures are wider though the number 

 of the gills is the same. 



PORICHTHYS NOTATUS, Grd. 



Plate XXV. 



Spec. Char. — Upper surface of head quite flat. An acute preopercular spine stretching across the opercle. Posterior 

 extremity of maxillar bone extending to a vertical lino drawn posteriorly to the orbit. Four series of pores on either side of the 

 body. A subgular and an abdominal series, as also several of these on tlio sides of the head. Upper regions dark bluish violet ; 

 sides and belly silvery grey. A sub-crcscentic vitta beneath the eye. 



SYU.—Porichlhys notaivs, Grd. in Proc. Acad. Nat. So. Philad. VII, 1854, 141 and 151. 



