62 



W. D. Lang — The Reptant Eleid Polyzoa. 



be modified and the distal angle be replaced by a sharp point 

 (Fig. ^) ; again, the distal angle or the two proximal angles, or all 

 three angles, may be rounded off (Fig. 10) ; and when this is 

 extreme the aperture becomes subtriangular (Figs. 4, 5, and 6) and 

 finally circular (Fig. 2). The extreme rounding of the distal angle 

 onlj' gives a semicircular aperture (Fig. 3). Finallj^ by the bulging 

 inwards of the sides a triangular aperture becomes trifoliate (Fig. 1). 



Figs. 1-11. — Diagrammatic representations of the apertures of Eleids. (See 

 explanation of figures at tlie end of the text, p. 68.) 



The following table determines the species of the reptant Eleids 

 regardless of zoarial characters. Species marked F occur abroad, 

 those marked B in Britain. Of those marked M the British Museum 

 has examples. 



The two species placed in brackets are repetitions, put where they 

 are in case variations in the shape of the aperture have caused 

 specimens of these species to be misplaced in the first instance, when 

 identified according to the table. 



The character of the presence or absence of closed zooecia is put 

 in the table, although its value as a specific index is considered 

 doubtful. 



( Ecptclca ligericnsis 



\ (d'Orbigny). F. 



A. Apertiires trifoliate. K^o closed zoa>cia 



E. Apertures circular. 



a. Apertures about ^ the diameter of the zoo;cia. | Eeptelea pyriformis 

 Xo closed zooocia j (Michelin). F. 



b. Apertures about f the diameter of the zocccia. \ (Eeptoceritites Roicei, 



No closed zooecia | Gregory. B, M.) 



^ . , • • 1 -N- 1 , . ( RepteJea actaon 



C. Apertures semicircular. JSo closed zooecia \ fd'Orhio-nv^ F 



