18G8.] BAKER SANTA CRUZ, PATAGONIA. 505 



cate, and frequently cross -jointed. The tail is a powerful organ, 

 more so than in the typical Lepidotl : the upper lobe is strengthened 

 by a series of strong scales imbricating the upper edge of the fin ; it 

 contains eighteen long rays : the lower lobe is composed of twenty 

 rays, and has the inferior margin invested with fulcral scales. All 

 the component rays are cross-jointed, and the extremities frequently 

 bifurcated. The head, in shape, resembles that of Pachycoi'mus, 

 being broader and more blunt-nosed than in Euynathus, but smaller 

 and more elongated than in Lepidotus. The lower jaw is straight, 

 and measures from 3 to 3| inches ; it is furnished with numerous 

 sharp hooked teeth of irregular size, resembling the dental apparatus 

 of the true Sauroid fishes. The maxilla is 2| inches in length ; the 

 teeth in this bone are smaller and more irregular than those on the 

 mandibles. All the head-bones are of dense structure, and have a 

 coarse surface-ornament composed of granules and blisters of ganoine 

 irregularly disposed in clusters here and there, the remainder of the 

 surface being smooth and lustrous. The scales on the anterior 

 part of the trunk have all the characters of the scales of the typical 

 Lepidotl ; but on the ventral surface of the body they assume an 

 elongated form, characteristic of the scales in this region of the 

 Eagnathi. This character is common also to two species now clas- 

 sified as Lepidotl, namely, Lepidotus Jimhriatns and Lepidotus serru- 

 latus, the former from Lyme Regis, the latter from Barrow-on-Soar. 

 In his desciiption of the latter species, Agassiz remarks upon this 

 elongation of the scales on the ventral surface ; and Pictet alludes to 

 the former as a species whose generic position is still doubtful. 

 Agassiz only knew it by some very fragmentary specimens ; perfect 

 ones have since been found, and prove that it had sharp teeth and 

 elongated ventral scales, although the body had the thickish outline 

 of the true Lepidoti. I am of opinion therefore that these two species 

 may be classified as a subgenus with the subject of this memoir, 

 under the name of Eidepidotus, and as forming part of the Sauroid 

 rather than the Lepidoid family. As far as our present knowledge 

 extends, this form is restricted to the Lower Lias. 



6. Note accompanying some Fossils /rom Port Santa Crfz, Pata- 

 gonia. By Capt. Thomas Baker, Lieut. Eoyal Naval Eeserve. 



[Communicated by the Assistant-Secretary.] 

 (Abstract.) 

 The entrance to the river Santa Cruz, which is about 134 miles 

 north of the Straits of Magellan, lies between a high steep cliff on 

 the south and a low shingle point on the north. The estuary of the 

 river runs in a north-w^esterly direction for a few miles, and then 

 divides into two branches : — a northern, which is a sluggish shallow 

 stream abounding in shoals ; and a western, which is of more im- 

 portance to navigation, and is the true river Santa Cruz. From the 

 estuary the western arm takes a south-westerly course, and then bends 

 sharply to the west, flowing between cliffs from 200 to 300 feet in 

 height, which at present are not washed by the river, being bordered 



