232 



niSTORT 



OF MASSACHUSETTS 





GENUS V. ACANTHIAS. Risso. 



no anal fin 



Two dorsal fins, with a spine before each ; first dorsal behind the line of the pectorals 

 the second dorsal over the space between the ventral and candal fins 

 Skin rough in one direction ; the scales heart-shaped, with 

 ward. Temporal spiracles large. 



a central spine directed back 

 Several rows of teeth in both jaws, cutting and sharp 



points directed outward and backward 



Acanthias AMERiCAOTS, JStorer. 



The Dog-fish. 



(Plate XXXVIII. Fie. 1. 1 a. Jaws.) 



nax acanth 



u 



it 



« 



it 



Spinous Dog-fish, Dekay, Report, p. 35S 

 Dog-fish, Atres, Bost. Journ. Nat. Hist 



amencaniis 



Color. All the upper part of the body is of a slate color, which is deeper upon the 

 head, and lighter below the lateral line. Body beneath, white ; a row of circular white 

 spots are situated just under the anterior portion of the lateral line, and a few similar 

 spots are irregularly distributed upon the back ; these spots, in some specimens, are 

 arranged with much more regularity than in others. The young of this species are 

 much more spotted than the adults. In several foetuses I have examined, there have 

 been noticed several white spots on the tops of the shoulders, — two in front of, and two 

 just behind, the first dorsal fin ; also spots on the sides, which, becoming confluent, form 

 a white band extending almost the whole length of the body. 



ely observe 



ipot 



In a male specimen, twenty-three inches in length, I could scan 

 upon its entire surface. 



Description. Body elongated, cylindrical, with a slight ridge on the back, which is 

 more perceptible between the dorsal fins. A distinct carina on each side of the abdo- 



posterior to the second dorsal fin. The entire surface is roug 



The head, which 



flattened above, and tapers to a blunted snout, is equal to one seventh the entire length 



The eyes are horizontally elongated ; the pupils are small, black ; the irides 



of the fish 



silvery with a cupreous 



The orbits are large, allowing great motion 



eyes, 

 head 



to the 



o o ~ 



The distance between the eyes is equal to more than one half the length of the 

 The temporal orifices are back of, and just above, the posterior angles of the 



