124 ANNALS OF SCOTTISH NATURAL HISTORY 



concerning this capture. It is not necessary for me to explain why, 

 at first, I accepted the record, which was based on a communication 

 to the " North British Daily Mail," as genuine, nor why I after- 

 wards was led to think that a mistake as to the species may have 

 been made. It will suffice if I say that I now find that the name 

 5. catulus has probably, through some inadvertence, been applied to 

 another species than the Larger Spotted Dog-fish. 



Specimens of a Dog-fish known as the Tope or Toper (Galeus 

 canis] have been occasionally landed at Girvan during the winter, 

 and it is very likely that the name 6". catulus in the " Daily Mail " 

 paragraph refers to specimens of this fish. At any rate, I have been 

 unable so far to obtain any satisfactory information regarding the 

 occurrence of the Larger Spotted Dog-fish, or Nurse-hound (Scyllium 

 catulus), in the Clyde estuary. 



The Lesser Spotted Dog-fish, or Rough-hound (Scyllium canicitlus\ 

 is occasionally taken in the Clyde in the trawl of the Fishery 

 steamer " Garland," but the other has not yet been observed. More- 

 over, the Larger Spotted Dog-fish is also absent from the list of 

 fishes captured by the SS. " Medusa," which belonged to Dr. (now 

 Sir) John Murray, which was so successful in its investigations into 

 the Fish and Invertebrate Fauna of the Clyde. 



It is possible, however, notwithstanding this negative evidence, 

 that Scyllium catulus may be, though rare, a member of the Clyde 

 fauna ; and as it bears a close resemblance to the more common 

 species and might be mistaken for it, a reference to one of the more 

 obvious differences between them may be of interest to those who 

 are not so familiar with these fishes. 



There are three kinds of Dog-fishes in Scottish waters which 

 have their skin ornamented with spots. First we have the Black- 

 mouthed Dog-fish (Pristurus melanostomus), readily distinguished 

 from the others by having the inside of the mouth of a black colour, 

 hence its name. The other two, as I have said, are in some respects 

 pretty much alike, but may be distinguished by observing the out- 

 line assumed by the posterior position of the ventral fins when they 

 are pressed together. If the ventral fins of the Lesser Spotted Dog- 

 fish (Scyllium caniculus) be pressed together so that the inner edge 

 of the one touches the inner edge of the other, their extremities will 

 together form a moderately sharp angle, and the posterior part of the 

 outer margins will slope away forwards and outwards. If the same 

 thing is done with the ventral fins of the Larger Spotted Dog-fish 

 (Scyllium catulus}, a very slight angle is to be observed, but the lower 

 edges of the fins form a nearly straight line athwart the fish, and if they 

 slope they do so only to a small extent. This difference is fairly 

 constant and reliable, whereas the difference in the size of the 

 spots, notwithstanding the names, is not always to be depended on. 

 T. SCOTT, Aberdeen. 



