343 



rotundatis ; deltidiis angustis ad lateres foraminis coalescentibus ; 

 valva ventrali depressa, transversim ovata ; dentibus cardinalibus 

 ut in T. psittaced; margine valvarum crenulato. 



A single specimen of this very interesting species was found in 

 the collection of the late G. Humphrey, without locality. This 

 and the T. psittacea are the only species that are not punctated. 



Piuictat(P. 



3. Terebratula Caput-serpentis (PL lxviii. f. 1 to 4. and 

 PL lxxii. f.116.) Lam. 



Testa ovata, rotundato-subpentagonali, albicante ; valvis subse- 

 qualiter convexis, longitudinaliter radiatim costellatis, costellis bi- 

 furcatis, granuliferis ; linea marginali lateraliter flexuosa, antice 

 subemarginata ; valva dorsali subrostrata, foramine mediocri, haud 

 integro, obliquo; area cardinali subdepressa, deltichis fere obsoletis ; 

 ossiculo interno (valvse ventralis) parvo, ~ longitudinis valva;, an- 

 tice arcuato, fornicato ; margine interno valvarum minutissime 

 crenulato. 



Shell ovate, of a rounded somewhat pentagonal figure, whitish; 

 valves nearly equally convex, longitudinally and radiately costel- 

 lated, the little ribs being dichotomous and granulated ; marginal 

 line flexuous on the sides, slightly emarginate in front ; dorsal 

 valve somewhat beaked, with a moderate sized perforation, which 

 is oblique and not entire ; the cardinal area is rather flattened and 

 the deltidia are nearly obsolete : internal appendages, (which are 

 always attached to the ventral valve) small, about i the length of 

 the shell, arched in front and vaulted ; internal edge of the valves 

 very minutely crenulated. 



This species, which is found on most of the northern coasts of 

 Europe, and which abounds on some of our own coasts, is also 

 found in the Mediterranean. It appears to us, however, to be 

 distinguishable without difficulty from the North American species 

 described by Couthouy under the name of T. septentrionalis. In 

 different stages of growth and under peculiar circumstances it has 

 had several names assigned to it, thus a young shell has been 

 named T. costata by Lowe, and T. aurita by Fleming ; and speci- 

 mens covered with an apparently pubescent epidermis (or a minute 

 hairy zoophyte?) have been named T. pubescens by Midler. We 

 have represented the emargiuated variety from the Mediterranean 

 at fig. 1 ; the entire and more gibbous variety from Oban at fig. 2 ; 

 the emarginated variety from Loch Fine at fig. 3 ; the rather com- 

 pressed and pubescent variety from the Norwegian coast at fig. 4 ; 

 and the nearly quadrangular variety at fig. 116. 



