42 HYGROMIA REVELATA. 
Var. occidentalis Moquin-Tandon. 
Helix occidentalis Moq.-Tand., Hist. Moll., 1855, p. 221, and pl. 17, f. 10-13, not of Recluz. 
The shell as described by Moquin-Tandon differs little from our British revelata, 
and the divergence shown by the anatomical drawings here reproduced may be due 
to the less rigorously precise methods formerly in vogue, and cannot be cleared up 
until the anatomy of the various forms has been carefully studied. 
Original Description.—‘‘ COQUILLE subglobuleuse, assez convexe en dessus et en 
dessous, & stries longitudinales demi-effacées, fines, inégales ; mince, fragile, couverte 
de poils courts un peu roides, peu luisante, transparente, d’un corné fauve légere- 
ment verditre. SPIRE composée de 445 tours assez convexes, croissant rapidement ; 
le dernier un peu grand, non caréné ; SUTURE profonde. SOMMET obtus. OMBILIC 
eo 8? @ 
Fic. 56. Fic. 57. 
Fic. 56.—Hedix occidentalis Moquin-Tandon (after Moquin-Tandon). 
Fic. 57.—Helix occidentalis, Coimbra, photographed from specimens collected by Prof. Nobre. 
petit. OUVERTURE oblique, ronde, un peu échancrée par l’avant-dernier tour. 
PERISTOME interrompu, subréfléchi, avec un bourrelet interieur plus ou moins épais, 
blane, & bords trés rapprochés, tres convergents; le columellaire trés arqué, réflechi 
sur ’ombilic. Hauteur 4-6 mill. ; diam. 5°5—8 mill.”—MoqQuiN-TANDON, op. cit. 
The strize of the shell are further noted as ‘‘ obliques et onduleuses, Poils long de 
0.75 mill., gréles, pointus, legerement courbes, un peu transparents, cadues.” 
The ANIMAL as described by Moquin-Tandon does not differ appreciably from 
the preceding account of the animal of Hygromia revelata. 
The animals of the two immature shells sent in Nov. 1887 by Mr. J. H. Ponsonby 
from Tangiers, had black and dusky bodies, with paler patches and marblings ; the 
fore-mantle was yellowish-white, with a few scattered black specks, rest of mantle 
silvery-white also speckled with black ; foot whitish; kidney whitish; liver or 
digestive-gland dark sepia-brown. 
The ALIMENTARY CANAL of the immature Helix occidentalis from Tangiers 
differs from that of adult H. revelata from Guernsey in the comparatively greater 
development of the salivary glands and the shortness of their ducts, the Guernsey 
shells having small, compact, secretory masses and very elongated ducts. 
fl 40 
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Fic. 58. Fic. 59. Fic. 60. Fic. 61. 
Fic. 58.—Alimentary Canal of very immature example of Hedix occidentalis, from Tangiers. 
Fic. 59.—Proximal portion of Reproductive system of A. occidentalis (after Moquin-Tandon). 
Fic. 60.—Penis-sheath and accessories of H. occidentalis, from Tangiers (greatly enlarged). 
fi. flagellum ; .s. penis-sheath; ». retractor ; v.d. vas deferens. 
Fic. 61.—Heart and Kidney or Renal organ of H. occidentalis, Tangiers (greatly enlarged). 
The REPRODUCTIVE SYSTEM of H. occidentalis as figured by Moquin-Tandon 
shows certain differences which if confirmed would probably justify its separation 
from H. revelata. The MUCUS-GLANDS are described as reduced to two nipples cleft 
at their summits and in comparison with those of H. revelata are figured shorter, 
thicker, and much more fused together, while there are no traces whatever of the 
dart-saes, ete., which are so perceptible in our species. The PENIS-SHEATH is quite 
in harmony with that of H. revelata, but the FLAGELLUM which in our species is 
short, thick, and subulate, is figured by Moquin-Tandon as somewhat regularly 
cylindrical, and described as short and slightly subulate, continuing the contracted 
distal end of the penis-sheath by a somewhat shorter appendix. 
The penis-sheath and appendages of the immature specimens sent from Tangiers 
by Mr. Ponsonby are almost identical with those of H. revelata. 
