420 Proceedings of the Royal Physical Society. 



Brit. Mus. ; Copenhagen Miis.). Azores (Agassiz, 2). Josephine 

 Bank (Stockhohn Mus., fide Agassiz). Florida Reefs, 79-183 

 fms. (PouKTALES, fide Agassiz, 2). Florida Bank to Antilles, 

 98-805 fms. (Agassiz, 5). Off Brazil, " Challenger," St. 122, 

 350 fms. (Agassiz, 3). 



ScuTELLiDiE, Agassiz. 



Test very depressed ; marginal incision and lunules present 

 or absent ; radiating partitions internally. 



8. Arachnoides, L. Agassiz. 

 Ambulacral petals diverging ; actinal grooves straight ; no mar- 

 ginal cuts nor lunules. 



18. Arachnoides placenta (Linne), L. Agassiz. 



1758. Echinus 2yincenta, Linne, Syst. nat., ed. x., p. 666. 



1841. EcMnarachnius placenta, Forbes, Brit. Starf., p. 178, cut. 



1841. Arachnoides placenta, L. Agassiz, Monogr. Echin., 2me Hvr., 



ScutelL, p. 94, pi. xxi., figs. 35-42. 

 1872. ,, ,, Agassiz, Rev. Echin., pp. 90, 530, pi. 



xiiift, figs. 1-4. 

 1874. ,, ,, Loven, Etudes, pi. viii., figs. 77, 78 



(peristome) ; ])\. li. (test). 



The reasons for doubting the claims of this species to a place in 

 the British fauna have been given above. 



Distribution. 



British Seas.— Fouldi, Shetland (Fokbes, 1) 1 

 Other Localities. — " New Zealand, Australia, East India 

 Islands, Burmah " (Agassiz, 3). 



SPATANGOIDA. 



Peristome actinal or frontal; periproct outside the dorso-central 

 system in the posterior interradium ; neither external branchia?, 

 jaws, teeth, nor perignathic girdle. 



Cassidulid^e, Agassiz. 

 Mouth central or subcentral, pentagonal, oblique, or elliptical ; 

 no plastrons nor fascicles ; tubercles neither perforate nor crenu- 

 late ; pairs of pores crowded close to the peristomial margin, 

 forming, with the single, swollen, and ornamented interradial 

 peristomial plates, " a floscelle." 



