MILAX GAGATES. 143 
The effect of insular conditions upon the coloration of this species is 
well marked; the broad effect being a general similarity which has a marked 
relationship to the two prevalent varieties characterizing the British Isles. 
In Madeira this species is of a more or less dark-brown colour, and has 
been described as var. maderensis Ckll. ; it may be regarded as an extreme 
form of the var. rava. 
The MZ. gagates of St. Helena, described as forma helenw, partake of the 
characters of the vars. plumbea and rava, and the same intermediate fea- 
tures are displayed by the forma ¢ristensis CkIl., from Tristan d’Acunha 
and Juan Fernandez. 
The Bermuda specimens on the contrary display a close relationship 
with the typical form, but show a flexuous keel, and are rather more 
opaque and rugose than is usual. 
The American examples of AZ gagates, perhaps better known under 
Cooper's name of MV. hewston?, differ but little from typical gagates; the 
body is blackish above, paler at the sides ; sole dull greyish ochreous ; keel 
not conspicuous in the living 
slug, but much stronger when | y, 
contracted in alcohol. ‘The ee Y 
internal structure agrees also i y |\ 
with gagates in all essential ae 
points, the oviduct being said Fis AG 
by Binney to be long and very marginal teeth of M. hewstoni 
tortuous, with a well-developed (his blyauagnificd yattes Emuey. 
sperm-duct ; the vagina very 
short, the large and globular 
spermatheca entering about the 
middle by a very short duct ; penis sac small, short, and cylindrical, but 
expanded and bulbous at the apex, where the vas deferens enters. 
The lingual membrane has a formula of 30 + 1+ 30, with fourteen perfect 
laterals, and shows symmetrical basal plates, and well-developed endoconic 
cutting points to inner lateral teeth, but the marginals are not bifurcated. 
Fic. 166.--Sexual organs of JZ. 
hewstoni (after Binney). 
Var. bedriage Less. & Poll., Monog. Limae. Ital., 1882, p. 59. 
Amalia mediterranea Ckll., Ann. and Mag. N.H., 1891, p. 331. 
Amalia mediterranea f. similis Ckll., op. cit., p. 332. 
Amalia gagates f. atlantica Ckll., op. cit., p. 330. 
ANIMAL black, lateral areas of the sole blackish. 
The sub-var. mediterranea CkIl. only differs from the var. bedriage in its 
larger size, measuring 56 mill. in length (in aleohol). It is described as of a rather 
dull black, and though somewhat shiny, quite opaque. 
The sub-var. similis Ckll. is smaller than the preceding, has an opaque-wrinkly- 
rugose and black body, a strong and rather flexuous keel; side-areas of sole greyish. 
The sub-var. atlantiea CkIl. is of ordinary dimensions, and also black, slightly 
transparent at the sides, body smooth, with rugve not well marked ; sole grey and 
slightly translucent ; jaw dark brown with a well-formed median projection. 
France—Var. bedriagw, Nice, in the Alpes Maritimes, Signor Bedriaga (Less. & 
Poll., op. cit.). 
Sardinia—Var. bedriagw, Signor Falchi (Less. & Poll., op. cit.). 
Sicily—Sub-var. similis, Catania (T. D. A. Cockerell, op. cit., p. 332). 
Spain—Sub-var. atlantica, Gibraltar, J. H. Ponsonby (T. D. A. Cockerell, op. 
cit., p. 331). 
Algeria—Sub-var. mediterranea, a specimen from East Algeria in the British 
Museum, received from Dr. Heynemann (T. D. A. Cockerell, op. cit., p. 331). 
The specimens in the British Museum, collected by Dr. Anderson at Hammam 
Meskontina, and referred to sub-sp. mediterranea hy Mr. Cockerell, are perhaps 
better placed under the sub-var. atlantica. 
Morocco—Sub-var. atlantica, Tangiers, J. H. Ponsonby (T. D. A. Cockerell, op. 
cit., p. 330). 
