TESTACELLA HALIOTIDEA. 



Internally, the eepeoductivk organs are more 

 complex than in the allied species, the penis-sheath 

 being terminated distally by a coical enlargement and 

 an abrnpt flexure, altliough Lacaze-Duthiers and others 

 figure the male organs, of what they atfirm to be this 

 species, without these adjuncts ; beyond the penis is the 

 epiphallus and a well developed and somewhat cla- 

 vate flagellum, which Lacaze-Duthiers affirms is 

 evaginated during pairing ; and which is furnished with 

 a slender lateral and a powerful distal retractor, the 

 latter affixed at the caudal extremity of the body ; the 

 VAGINA and atkium are usually rather short ; the 

 large oval spermatheca is attached to the ovidtict 

 near the base of the albumen gland, and has a short, 

 thick and fusiform duct ; ovotestis composed of small, 

 loose, oblong follicles with a tortuous duct. 



The ALIMENTARY CANAL lias the simple doubly- 

 flexed course characteristic of the genus Testacella. 

 The CESOPIIAGUS is extremely short, tlie CROP whitish, 

 longitudinally and transversely wrinkled, and about 8 

 mill, long, beyond which the canal is constricted ; at the 

 first bend of the gnt, the vestigial stomach shows as a 

 purplish enlargement, and receives the bile ducts from 

 the ample light-brown liver ; a short distance beyond the 

 canal gradually narrows and runs backward as the rectum to the anus. 



The eetractors of the right and left tentacles are separate, quite independent 

 of each other, and almost symmetrically fixed near their respective foot-margins. 



The LINGUAL SHEATH is very long, somewhat 

 compressed, tapering obliquely behind, and leaching 

 back nearly to the hinder extremity of the body, 

 RETRACTORS Consisting of three or four paitially 

 fused terminal muscles, secured to the skin of the 

 left side beneath the shell, and in addifciira ten to 

 fifteen pairs of oblique ribbon-like lateral muscles, 

 arising from tVie left side of the hinder half of the 

 sheath, the most anterior being about six mill, long 

 and attached to the skin on the left side of the mid- 

 dorsal line, while the shorter and more posteriorly- 

 placed muscles are fixed nearer and nearer to the 

 sole, to which the last few muscle-bands aie fixed, close by the straight terminal ones. 



The LINGUAL TEETH are stout, arcuate, and distinctly barbed, with the convex 

 apical surface furnished with a somewhat distinct cutting blade, the median 



Fig. 8. — Se.\u.T[ organs of 

 Testacelta haliotiiUa X l^. 



(Horsham-, Mr. T. Whitaker). 



a.th.g. albumen gland ; ep. epi- 

 phallus ;y?. flagellum; ot. ovo- 

 testis ; ov. oviduct ; p.s. peuis 

 sheath ; r. ///. retractor muscle ; 

 sp. spermatheca ; spui. .sperm 

 duct ; v,d. vas deferens. 



Fig. 9. — Lingual sheath of 

 Testacella haliotidca^ Bristol, col- 

 lected by Mr. J. W. Cundall, illu.s- 

 trating the retractor muscles of the 

 tentacles and lingual sheath. 



IS 



Fig. 11. — Isolated teeth from 

 Fig. 10.— Transverse row of teeth from the odontophore of the fifth and thirteenth longitu- 



TestaccUa haliotidea X 20, from Oxford, collected by Professor dinal rows of the radula of T. 



Poulton, photographed by Mr. T. W. Thornton. haliotidea X 10. 



apophysis large and distinct, basal enlargement slight, and the transverse rows more 

 acutely angulatedi than in the allied species. According to Lacaze-Duthiers, the 

 vestigial median teeth are discernible with a magnifying power of 200-300 diameters. 

 The dental formula^ of an Oxford example is 



• \"'"rrr? ' ^^ 38=i368 



1 The figure of the dentition given in Woodward's Manual, p. 298, and copied therefrom as that of 

 Testacella haliotidea by many authors, is not really that species, but should be assigned to 7. 7iiauget. 



2 Monog. i., p. 262. 



