[ 617 ] 



Notes and Memoranda. 



By 

 H. M. Kyle, D.Sc. 



(With Plate III.) 



Malformation in Tub (Trigla lucerna, Bloch). 



During the past year (1902) several cases of peculiarly shaped 

 gurnards were reported from Brixham and Plymouth, and three 

 specimens eventually fell into my hands. They are hunchbacked in 

 form, and are so distinct from the common type that in the days 

 of Couch and Parnell they would have been raised to the dignity of a 

 separate species. No records of such malformations in the gurnards 

 — though common enough in fresh-water forms, as perch and trout — 

 have ever been made so far as my knowledge goes, so that a brief 

 description seems advisable. 



In essential characters they are really the tub, and only the peculiar 

 longitudinal compression of the vertebrse, with consequent shortening 

 of the total length, and alteration in the proportions of the various 

 parts of the body, mark them off from this species. 



The colouration of the body has for the most part disappeared, as 

 it was some time after capture before they were seen and preserved, 

 but the characteristic deep blue of the large pectorals is still con- 

 spicuous. The body is smooth, except for the marginal spines at the 

 base of the dorsal fins. These marginal spines are, as usual, twenty- 

 five in number. The fin-ray formulcE are the same as in the 

 ordinary tub. 



D,jQ^; A, 16-17; P,(l + 8 + 2) + 3;V,^C, 4 + 9 + 3. 

 Vert. 11/21 ; scales on lateral line, 75. 



The specimens are thus in all essential respects the T. lucerna; 

 their appearance, however, is very different. The body between the 

 head and tail is short and stunted in proportion to the size of the 

 head ; it is likewise deeper and thicker. In two of the specimens 

 this appearance extends uniformly from head to tail (Fig. 1), but in 

 the third there is a sudden contraction just behind the abdominal 

 region, which recalls the hog-backed variety of trout. 



The total lengths from the snout to the caudal fork are 20-2 cm., 

 22-2 cm. for the first two, and 22 cm. for the third. The girths, 



