744 



AETHROPODA 



PHYLUM VII 



being interlocked on the dorsal edge, but are only in apposition on the ventral 



edge, where they were undoubtedly capable of dehiscence for 

 the protrusion of the appendages. This is the most primitive 

 genus of the group. Ordovician to Devonian. 



Family 2. Turrilepadidae Clarke. 



Body ivith four to six vertical columns of triangular plates, 

 two of the columns being small, accessory and sometimes much 

 modified in shape. Gaiidal plate patelliform, axial. 



Turrilepas Woodw. (Plumulites a b 



Barr.) (Fig. 1438). Body elongate- 

 Silurian ; Rociiester, New conical with four to six columns of 



lork. Jjorsal, lateral and 



ventral views. large triangular overlapping scales, 



some of which are keeled in the 

 middle. Besides having concentric striae, the surface may be 

 radially lined or punctated. Cambrian (?) to Upper Devonian. 

 Strobilepis Clarke. Composed of four columns of over- 

 lapping plates, two of which are of large and eqnal size. 

 Of the other two intervening columns, one consists of a 

 few very small plates, and the other is modified into a series 

 of grooved sj^ines which appear to overlap one another at 

 their bases, and to lie opposite the column of small plates, 



Fid. 1437. 

 Lepidocolcns Hnrhi Clarke. 



Fig. 143S. 



Caudal extremity terminated by a circular, conical, axial England. A, Compiet 

 plate, against the sides of which lies the first plate in each putes,' enlarged '(after' 



column. Middle Devonian. 



TurriUpas imghtianus de 

 Koninck. Silurian ; Dudley, 

 ,e indi- 

 Isolated 

 Wood- 

 ward). 



Family 3. Lepadidae Darwin. (Goose Barnacles). 



Shell pedunculated, composed mainly of the paired terga and scuta, the impaired 

 carina, and a variable number of small calcareous plates, some of which cover the 

 flexible peduncle ; others take part in the capitulum. The calcareous plates are never 

 fused. 



Archaeolepas Zittel (Fig. 1439). Peduncle flattened, the two principal surfaces 



FlO. 1439. 



Archaeolepas • redten- 

 hachcri (Opp.). Litlio- 

 graphic Stone ; Ke!- 

 heim, Bavaria. Vi- 'i 

 Carina ; li, Rostrum ; 

 S, Scutum ; T, Tergum. 



Fl(i. 1440. 



A, Loricula laevisHma Zitt. 

 Senonian ; Dulinen, West- 

 phalia. Vi- B, C, Loru-uta 

 syriaca Dames. Cenomanian ; 

 Lebanon. Vi 'I'l'l "h- 



Fig. 1441. 



Scalfiellum gallicum 

 Hebert. Upper Cretace- 

 ous ; Meudon, near Paris. 

 2/, (after Hubert). 



with four to six, the narrow sides with two columns of small scales. The capitulum 

 is composed of triangular scuta, two large trapezoidal terga, a short unpaired carina, 

 and a minute rostrum. Upper Jura to Lower Cretaceous. 



Loricula Sowb. (Fig. 1440). Peduncle squamous. Capitulum with two scuta, 

 two terga, four lateralia and a very narrow carina. Cretaceous. 



