1902.] PLECTOGNATHOUS FISHES. 



299 



enlarged tubercles more prominent. Soft dorsal and anal similar, 

 rounded, their longest ray half as long as the dorsal spine. 

 Pectoral scarcely longer than the gill- opening. Caudal rounded. 

 Caudal peduncle deeper than long, with two pairs of barbs on 

 each side as in the preceding species. Yentral spine moderate, 

 barbed. Scales as minute granules. 



Greyish, with rounded lighter (? light blue) spots on the sides 

 of head and body. Upper part of head and body, above a line 

 from the tip of snout to the eye and thence to the last dorsal ray, 

 brown. Lower part of the body with a similar brown area. Fins 

 immaculate. 



A single specimen from Tahiti, 175 mm. in total length. 



Yery closely allied to the preceding species, differing chiefly in 

 the more concave snout, more strongly armed dorsal spine, and 

 colour. 



PSEUDOMONACANTHUS DEGENI, n. Sp. (Plate XXIV. fig. 1.) 



Depth of body equal to length of head, 3 times in the total 

 length. Snout slightly convex, abovit 3| times as long as the eye- 

 diameter, which is equal to the interorbital width. Gill-opening 

 about equal in length to | the eye-diameter, its upper end below 

 the hind margin of the eye. D. II, 34. A. 33. Dorsal spine 

 above the hind margin of the eye, without ba,rbs, its length 2f 

 in that of the head ; second spine scarcely visible. Soft dorsal and 

 anal similar, rather elevated anteriorly, the rays increasing in 

 length to the eighth or ninth, which is the longest and equal to 

 half the length of the head, thence decreasing to about the 

 twentieth, the rest subequal. Pectoral almost as long as the 

 dorsal spine. Caudal rounded, more than half the length of head. 

 Caudal peduncle longer than deep. Scales minute, shagreen-like. 

 Ventral spine small. 



Greyish, with blue spots on the sides of the head and anterior 

 part of the body, and on the caudal peduncle. Som^e faint oblique 

 blue lines on the sides between dorsal and anal fins. Fins green. 



A single specimen, 190 mm. in total length, from Melbourne 

 Market, Australia. Mr. Degen sent with the fish a drawing 

 showing the colours when fresh. 



This species is closely allied to Pseiulomonacanthus modestas, 

 Gthr., ayrcmdi Gthr., and septentrioncdis Gthr., which it re- 

 sembles in physiognomy and in the shape of the fins, but all 

 these have distinct barbs on the dorsal spine. 



Tetrodon inermis Schlegel. 



This species was considered by Giinther to be a variety of the 

 Atlantic T. Icevigatus, and the descriptions of Schlegel and Day 

 (Fishes of India, p. 701, pi. clxxx.) have not sufficiently pointed 

 out the features which distinguish it from that species, the most 

 noticeable of which are as follows : — In T. inermis the body is 

 much broader and deeper in proportion to its length, there is no 

 distinct lateral fold in the abdominal region, and the spines on 



