COCKERELL : ON THE JAMAICAN SPECIES OF VERONICELLA. 25 



what particular forms of coloration can be used, is only to 

 be learned by experience. Thus, the variety coffece, found 

 at moderately high altitudes, is so far as observed sufficiently 

 constant in colour to be readily recognised. The var. 

 virgata, distinguished by less marked peculiarities of colour, 

 is always constant so far as noticed. Doubtless in both 

 cases intergrades will be found, but it is probable that 

 several such local races of V. sloanii — indicating the first 

 steps toward the formation of species — will be found in 

 Jamaica when a thorough search is made. Such local 

 races will present variations among their members, but the 

 average characters of each will be found to be different, 

 though one may intergrade with another where their 

 areas join. Among the specimens lately examined, three 

 (Nos. 18, 2, and 9) were observed to be very conspicuously 

 speckled, and we thought a distinct variety might be indi- 

 cated. They agreed very nearly in the number of filiform 

 glands, but in the length of the glands they disagreed, and 

 after comparing their characters in detail, we gave up all 

 idea of separating them under a distinct name. In this 

 case, apparently, the colour character was of no use for 

 purposes of classification. 



In the descriptions given below, the colour-characters 

 are often given in italics, to draw attention to contrasts in 

 this respect between anatomically-similar slugs. 



(4.) Distance of female orifice from head : varying from '51 (Nos. 15 

 and 8) to '60 (No. 9) of total length. These variations 

 cannot be correlated with other characters. 



(5.) Distance of female orifice from sole: varying from | mm. to 2, 

 or (in the specimen of 71 mm. long) 2| mm. It is doubtful 

 whether these variations have much significance. 



(6.) The penis is quite variously curved and twisted, the position it 

 assumes when the animal is killed being probably acci- 

 dental. Its length varies from 4^ (No. 7 ) to 13 (No. 16) 

 mm. The smaller measurement probably denotes some 

 immaturity, although No. 16, which had the longest penis, 

 was a slug only 1 mm. longer than No. 7. 



(7.) The penis retractor may be described as short and thick, but it 

 is commonly attached to a stout transverse fascia, which 

 represents its two divergent tendons. Such a condition is 

 described below as two retractors, though it might be more 

 correct to say retractor two-headed. In certain specimens 

 a 2 



